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             Research Paper 2011


     Title: Effects of menstrual cycle on joint
laxity and muscle strength


   Author: Juliette Taylor


   Supervisor: Rebecca Morrison




       The British School of Osteopathy
      275, Borough High Street, London SE1 1JE
Abstract:


Background: Studies have shown an increase in oestrogen levels across the

menstrual cycle (MC) with an increase in muscle strength and joint laxity

independently. However no research has yet been conducted into whether a

relationship is demonstrated between these two parameters.


Objectives: Feasibility study to identify a correlative change in joint laxity and

muscle strength across one complete MC.


Method: Twenty female, British School of Osteopathy (BSO) students aged 24-

45 who reported normal menstrual cycles (28-32 days) participated. Joint laxity at

the metercarpo-phalangel (MCP) joint and handgrip strength were measured at

three phases of the MC: menstrual (days 1-4), follicular (days 12-14) and luteal

(days 19-21).


Results: No significant variation or relationship in joint laxity or muscle strength

could be detected during the three phases of the MC.


Conclusions: No association was found between hand grip strength and joint

laxity as measured by the Hyperextensometer and Dynamometer however, due

to the variance in sex hormones found between females, individual variations and

hormone analysis is further required to distinguish whether there is a relationship

between these two parameters across the MC.


Keywords: Menstrual cycle and muscle strength; menstrual cycle and joint laxity;

menstrual cycle and osteopathy.
                                         1
Introduction:


Menstrual cycle (MC):


During their reproductive years females are exposed to rhythmic fluctuations in

hormone levels during their MC. These phases are generally referred to in three

phases: menstrual, follicular and luteal. Research has shown that both oestrogen

and progesterone concentrations are low during menses, with a rise in oestrogen

during the follicular phase, reaching a peak just before ovulation and then

dropping sharply. Oestrogen levels along with progesterone then rise again

reaching a broad peak during the luteal phase (Figure 1) (Slauterbeck et al, 2002

pp. 277).




Figure 1. Changes in concentration of oestrogen and progesterone during the

menstrual cycle.


It is well known that these hormones affect both the autonomous nervous system

and metabolic functions, so that athletic performance as well as certain important

parameters change along with the menstrual phases (Reis et al, 1995 pp. 545).

                                        2
These hormones have profound effects on all body tissues including connective

tissues (Sandler, 2006 pp. 48).


The influence of oestrogen and progesterone on muscle strength and joint laxity

has been widely discussed.


MC effects on muscle strength:


Study findings in this area are divided over whether muscle strength is affected

by the MC. A number of researchers have found that when oestrogen levels peak

just before ovulation it has a strengthening action on skeletal muscle. Sarwar et

al (1996) found that the quadriceps were stronger between days 12-18 and

Phillips et al (1996) reported adductor pollicis increased in strength during the

follicular phase. Previously Phillips et al (1993) linked the decrease in oestrogen

seen in the menopause with decreased strength compared to those on Hormone

Replacement Therapy (HRT), where strength was maintained. Bambaeichi et al

(2004) concluded that isometric contraction of the knee flexors and extensors

were greatest during ovulation phase.


Davies et al (1991), who also determined the phases by counting days

(corresponding with Phillips et al, 1993; Sarwar et al, 1996 study), contrastingly

concluded that it was during the menses phase, days 1-4, where oestrogen and

progesterone levels were low, that attributed increased hand grip strength.


Conversely Montgomery and Shultz (2010), who did a similar study to

Bambaeichi et al (2004), found no significant change in muscle strength despite

                                          3
the marked rise in ostetradiol levels and combined rise in oestradiol and

progesterone found in participants.


Unlike Bambaeichi et al (2004), who only measured eight females (age 30 ± 5)

and did not measure serum hormone concentrations, Montgomery and Shultz

(2010) measured 71 females (age 18-30), of which participants were tested

according to their own individual hormonal profile in the luteal phase, thus making

their results more significantly valid. However, these findings were limited to only

two different times of measurement during the MC, whereas Bambaeichi et al

(2004) measured at five points.


Several other studies have found no changes in skeletal muscle strength: by

measuring hand grip strength and maximal isometric quadriceps strength, (Janse

de Jonge et al, 2001); knee extension and flexion strength or endurance,

(DiBrezzo et al, 1991) and changes in mechanical properties of human muscle

and tendon during MC (Kubo et al, 2009).


The lack of clarity surrounding the MC on muscle strength might be linked to the

variation in experimental design. Throughout the above studies, various

measurement methods of muscle strength were used, with varying numbers of

participants, determination of the cycle phase and variations in oestrogen levels

found in different subjects in the same phase of the MC. More research is

therefore required in this field to obtain a clearer picture about the relationship

between oestrogen and muscle strength in the MC.



                                          4
MC effects on joint laxity:


Studies suggest that women generally have greater knee joint laxity than males

(Deie et al, 2002), and whilst this could be linked to sex hormones a similar

debate on the relationship of the MC on joint laxity exists.


Karageanes et al (2000) study showed that although the presence of sex

hormones, particularly oestrogen, may indeed predispose females to higher

anterior cruciate ligament (ACL) injury rates, they did not find any evidence that

hormonal level changes equate with significant ACL laxity changes. This

particular study, however, only measured female adolescent athletes with the

mean age of 15.65 years ± 0.98. De Souza et al (1998) showed that a high

frequency of luteal phase deficiency and anovulation in recreational runners and

relative inconsistency between MC could suggest why the athletes measured

showed no significant findings.


In contrast Shultz et al (2004; 2005) showed that transient increases in knee

laxity occurred in women across the MC as a function of changing hormones.

Heitz et al (1999) measured laxity as well as hormone levels and recorded an

increase in laxity with the increasing levels of oestrogen associated with the

follicular phase. Changes in hormonal concentrations over the MC may be

related to the occurrence of peripheral joint laxity, possibly compounding the risk

of injury (Heitz et al, 1999; Lunen et al, 2003). Slauterbeck et al (2002) reported

that a significantly greater number of ACL injuries occurred on days one and two

of the MC and that 26 of 37 athletes tore their ACL’s during the follicular phase of
                                          5
the MC. Shultz et al (2004) showed similar results using actual serum hormone

levels to define cycle phases and concluded that increased laxity in females

appeared to coincide with a rise in oestradiol levels. Sandler (2006) furthermore

reported that oestrogen had an important responsibility in laxity effect found in

the metacarpo phalangeal (MCP) joint of the index finger.


Sex hormones appear to influence the strain behaviour (Deie et al, 2002) and

metabolism of the ACL. The fluctuations in these hormones across the MC have

been implicated as a potential risk factor for ACL injury in females (Slauterbeck et

al, 1999; as cited in Shultz et al, 2004 pp. 1). The mechanism of increased injury

rate remains uncertain with possible explanations including sex differences in

ligament or muscle strength, training history, anatomy and conditioning

techniques (Heitz et al, 1999 pp.145).


Rationale:


Despite the controversy on the effects of sex hormones on muscle strength and

joint laxity and the consequently higher incidence of injury in female athletes to

date, there has been no published information available as to any direct

correlation in muscle strength and joint laxity during the MC. With various studies

concluding that joint laxity is greatest when oestrogen levels are rising and some

studies showing similar effect on muscle strength, it is therefore feasible to

conclude that the two parameters could be related and may ensure stability at a

joint.



                                         6
Understanding how hormone mediated increases in laxity affect synovial joint

biomechanics and resultant neuromuscular control of the joint, will help further

elucidate the potential role that laxity and female sex hormones play in injury risk.

Therefore the purpose of this study was to evaluate the possible associations

between joint laxity and muscle strength during one MC.


As this was an undergraduate dissertation, with funds, time and subject

limitations, the researcher felt that this study would be best conducted as a

feasibility study, and if significant data was reached it could provide data towards

further research on this subject on a larger scale.


Aims and Objectives:


The present study was designed to measure female students at the BSO at three

separate stages of the MC by counting the days, with first day of menses as day

one. The stages were determined according to the three major changes in the

fluctuating sex hormone levels seen during a normal MC of 28-32 days, used in

the Davies et al (1991) study.


Day 1-4, signifying low progesterone and oestrogen levels


Day 12-14, signifying high oestrogen


Day 19-21, signifying high oestrogen and progesterone.


The handgrip strength test was chosen to determine muscle strength as it was an

‘explosive’ type muscle test, therefore least likely to be affected by the


                                         7
psychological influences of MC. The hyperextensometer was used to measure

joint laxity. Sandler (2006) recommended this piece of equipment as an effective

measure of joint laxity as it was a non-invasive procedure that was quick and

simple. Furthermore, he stated that measuring change at the MCP joint would be

representative of a global change on all body tissues in relation to the circulating

sex hormones.


The objective was to gain knowledge for osteopaths about the potential links

between the events in the MC with change in muscle strength and joint laxity, so

as to aid awareness in adapting their approach to diagnosis, treatment and

management when treating physically active females in their reproductive years.


Hypotheses:


   1. Women with normal and predictable MC’s will experience significant

      change in both joint laxity and muscle strength throughout the different

      phases of their MC.


   2. There is a relationship between change in joint laxity and muscle strength

      during the different phases of the MC.




                                         8
Method:


Subjects:


Participants were recruited from the BSO via email invitation to all female

students (Appendix 1).


Inclusion and exclusion criteria:


Table 1 outlines the inclusion and exclusion criteria applied in this research:


Table 1: Inclusion and Exclusion criteria

Inclusion:                                      Exclusion:
   Signed consent form (Appendix 2)               History of inflammatory joint disease

                                                    and/or arthritis
   Female BSO student

                                                   Diagnosed with hyper-mobility and/or
   Aged between 18 and 45 years
                                                    joint laxity
   Regular and predictable menstrual
                                                   Current injury to dominant hand or
    cycle of 28-32 days
                                                    arm.
   Women with disabilities were eligible
                                                   Pilot study participants
    to take part in the study as long as

    they were able to perform the hand

    grip test.




                                            9
Ethics:


The research proposal was ethically approved by the BSO Research Ethics

Committee. All participants were given an appropriate Participant Information

Sheet (PIS) (Appendix 3) and were required to sign a consent form (Appendix 2).


Design:


This piece of research was an observational study which employed a

convenience sample of female students who had regular and predictable MC of

28-32 days.


The dependent variables were the three different stages of the MC: menstrual,

follicular and luteal, and the independent variables were joint laxity and muscle

strength.


Measurements:


Equipment:


Joint Laxity:


The equipment used was the Joint Hyperextensometer first designed by Jobbins

et al (1979).


A hyperextensometer (Figure 2) measures the extensibility of the MCP joint when

a pre-set torque of 2.6kg/cm2 (0.26Nm) is applied (Jobbins et al, 1979). This

piece of equipment was calibrated before the recordings of this study began.


                                       10
Fig 2: The hyperextensometer from above


Before measurement the indicator pointers were set to zero and the rotator knob

was rotated counter-clockwise until a click was heard ensuring that the clutch

mechanism had been reset (Figure 3).




                                              Rotator knob


Fig 3: The hyperextensometer from the front, set at zero.


The participants’ elbow was held at 90 degrees, with their forearm facing

downwards. Velcro tap was strapped around the first interphalangeal joint of the

participants’ index finger of their dominant hand, ensuring that the rotational axis

of the MCP joint was parallel to the axis of the operating shaft (Figure 4). The

participants’ hand was made secure by placing the researcher’s hand on top so

that measurement was specific to the MCP joint. The knob was then rotated with

                                        11
the researcher's right hand in a clockwise direction until the pre-set level of

torque was reached and the clutch slipped. The amplitude of rotation was then

measured on the protractor scale and recorded (Figure 2). Three readings were

taken so that an average value could be recorded.




                                    Operating shaft




Figure 4: Index finger of right hand strapped into the hyperextensometer.


Muscle Strength:


A Lafayette Instrument Hand Dynamometer (model 78010) was used to measure

the maximum isometric strength of the hand and forearm muscles. The testing

range on a dual scale is 0 to 100 kilograms / 0 to 220 pounds.


The participant held the dynamometer in their dominant hand, with their arm at

right angles and the elbow by the side of their body. The base rested on the heel

of the palm, while the handle rested on the middle four fingers. When ready, the

subject squeezed the dynamometer with maximum isometric effort, which was

maintained for about 5 seconds; no other body movements were allowed. The

participant was strongly encouraged to give a maximum effort.
                                       12
The dynamometer produced a measurement of force in Kg. This test was

performed three times with an interval of 2 minutes.


The dynamometer was calibrated after every use so to ensure that all the

measurements taken were valid.


Pilot:


A pilot study was conducted so as to allow the researcher an opportunity to

become efficient and sufficiently skilled in using the research equipment involved

in the study. An invitation to participate in the pilot study was emailed to all

female students from the BSO, of which the first five participants who conformed

to the inclusion and exclusion criteria in the PIS specific to pilot study (Appendix

4) were recruited.


A signed consent form was required by all participants before they took part in

the pilot study.


Participants were tested on one occasion and the procedure followed was exactly

as per the main study, except the participants were tested twice - by the

researcher and by an experienced user of the equipment.


The data collected from both researcher and experienced user were then

analysed by way of a correlation test to determine inter-rater reliability.




                                          13
The pilot study was successful and no changes were required to be made to the

procedure and the researcher was confident and efficient in using the equipment

required for this study.


Procedure:


The first twenty individuals who responded positively to the invitation email were

selected to take part in the study.


The PIS was read and consent form signed.


Information regarding the different phases of the cycle was given to the

participants so that they could work out from their menstrual cycles what days

they were required for testing. Joint laxity and muscle strength measurements

were taken on three separate occasions: during the menstrual stages (day 1-4),

the follicular phase (days 12-14) and the luteal phase (day 19-21).


Measurements were taken over one menstrual cycle.


Analysis:


The raw data was entered into SPSS version 18 for data analysis.


Muscle strength and joint laxity measurements were tested for normality by using

the Shapiro Wilk test. As the data was found to be normally distributed, paired t-

tests were carried out in order to identify if there were differences in individual

variables between the three stages of the MC.



                                        14
The possibility of an association between laxity and muscle strength were

identified by using correlation tests using the Pearson’s correlations test.


Statistical significance was set at p<0.05.




                                         15
Results:


Twenty BSO students volunteered to take part in the study, all of whom had a

regular and predictable menstrual cycle of 28-32 days. All participants were

female and had a mean age of 32 years (SD = 6). Table 2 shows the mean and

SD values for joint laxity and muscle strength over the three stages of the

menstrual cycle.


Table 2: Means and SDs for joint laxity and muscle strength over the three

stages of the menstrual cycle (†outlier included).


                                        Menstruation      Follicular         Luteal
            Measurements
                                        (M)               (F)                (L)
            Joint Laxity
                                        50.1 ± 17.1       54.1 ± 15.0        52.9 ± 15.7
            (Degrees)

            Muscle Strength (Kg)        29.4 ± 4.3        29.4 ± 4.7         28.6 ± 4.1†
† There was no difference in outcome of significance between original data with the outlier and data with

outlier removed and therefore original data was used.


Paired t-tests were carried out to examine whether there was a significant

difference in muscle strength and joint laxity between the three stages of the

menstrual cycle, as the data met the assumptions of normality using a Shapiro-

Wilk test (Joint laxity - M: p=0.602, F: p=0.670, L: p=0.139; Muscle strength - M:

p=0.985, F: p=0.510, L: p= 0.050).


Three pairings were analysed using paired t-tests: (i) M and F (ii) M and L and

(iii) F and L for both joint laxity and muscle strength. No significant differences

were found between the pairings (Table 3).


                                                     16
Table 3: Paired t-tests for muscle strength and joint laxity comparing 3 phases of

menstrual cycle.


                                                       Muscle
                                     Joint laxity
                 Pairing                              strength
                                         t, p            t, p
                 (i) M and F     -2.027, 0.057      0.053, 0.959

                 (ii) M and L    -1.407, 0.176      0.871, 0.394

                 (iii) F and L   -1.407, 0.434      0.805, 0.431



Pearsons correlation tests were carried out between muscle strength and joint

laxity for the three stages of the menstrual cycle. No significant correlation was

identified (Table 4).


Table 4: Pearsons correlation between change in joint laxity and muscle strength

over one menstrual cycle.


                   Phases of cycle      R value      P value
                                        0.046        0.846
                   Follicular
                                        -0.095       0.691
                   Luteal
                                        -0.164        0.488
                   Menstrual




                                         17
Discussion:


This study set out to measure explosive muscle strength in the form of hand grip

strength and joint laxity at a peripheral synovial joint during the three phases of a

MC, with the intention to detect if there were any changes across the phases and

whether there was a relationship identified between the two variables.


Main findings of the study were that there was no significant variation between

both muscle strength and joint laxity during one MC and secondly no relationship

was reported between the two. Therefore both hypotheses for this study were

rejected.


This confirmed the earlier findings which found no change in hand grip strength

across the menstrual cycle: Janse de Jonge et al (2001) and Lebrun (1993); but

contradicted the reports of Davies et al (1991); Phillips et al (1996) and Sarwar et

al (1996).


Similarly to the current study, Lebrun (1993) found no detectable cyclical

difference in handgrip in a cross-sectional study of young women; however

Phillips et al (1996), who reported an increase in strength during the follicular

phase, stated that it was easy to miss the changes in force with hand grip

strength because the changes were rather small. Their study showed that muscle

cross-sectional area (CSA) varied greatly between individuals and therefore

compared the relative force changes during a cycle for each subject to avoid the

large variance in force demonstrated in their subjects. This enabled small cyclical

changes in force to be detected, which could be missed if means of absolute
                                         18
force for subjects with very different muscle sizes were compared at different

points of the MC.


Janse de Jonge et al (2001), despite no change in muscle function parameters,

found a large variation in hormone concentrations throughout the cycle but also

within each menstrual phase. Especially during the late follicular phase the

variation in hormone levels was very large, with a range from 157 to 1038 pmol 1 -
1
    for oestrogen concentration. Rapid fluctuations in the reproductive and pituitary

hormones could occur at any time during the day throughout the MC and could

therefore explain the variation in results between studies.


Shultz et al (2004) found a similar variance in hormone concentrations and knee

laxity between their subjects. Overall their study concluded that changes in sex

hormones mediate changes in knee laxity across the MC, however stated the

strength of this relationship, the relative contribution of each hormone and

associated time delay are highly variable between women. The females in their

study varied considerably in length of their cycle (both follicular and luteal

phases) as well as the hormone phasing and absolute changes in hormone

levels across their cycle.


Despite studies reporting significant changes in either muscle strength or joint

laxity across the MC by counting days (Davies et al, 1991 and Sarwar et al,

1996), the variability in women concluded by Phillips et al (1996) and Shultz et al

(2004) could explain why overall no significant changes were seen in the subjects

measured in the current study. Furthermore, anovulatory cycles may occur
                                          19
despite regular periods, affecting hormone levels and lengthening the follicular

phase more than the luteal phase (Friden et al, 2003 pp.240).               Therefore,

although no relationship was found in the current study, to draw valid conclusions

on the effects of MC on both muscle strength and joint laxity, it is necessary to

measure actual hormone levels so to avoid non ovulatory MC’s and to certify the

significant phases of the MC for each subject.


The findings of this study suggested that there is no change in joint laxity as the

MC progresses, agreeing with earlier findings of Karagenanes et al (2000) and

Lunen et al (2003). However, this rebuts the previous research by Sandler (2006)

who also used the hyperextensometer to measure joint laxity. He concluded an

increased mobility as the cycle progressed and the presence of specific hormone

in the specific phase was probably the important contributing factor relating to the

change in laxity within the phase. During data collection of the main study, on

occasion, one of the readings was found to be very different from the others. This

particular occurrence was experienced in Sandler’s (2006) study who

recommended avoiding outliers by conducting recordings in threes until three

consecutive readings were recorded. In doing so there could be debate as to

whether repeated measurements could cause increased laxity at the joint, thus

giving a possible un-true reading of laxity at that time. With this in mind, reliability

of this piece of equipment as a measure of joint laxity is questionable due to the

occurrence of outliers and therefore possibly affecting end results.




                                          20
A further limitation of this study was that the level of physical activity was

unknown in the population of students measured. Janse de Jonge et al (2001)

and De Souza et al (1998) concluded that, along with their findings, one cannot

assume a consistent menstrual cycle with regular hormone concentrations for

recreationally active women. As this was not taken into consideration, it is

unclear whether the participants were recreationally active and consequently

(without hormone analysis) it cannot be assumed that all subjects ovulated in the

current study, thus impacting on findings and the overall validity of results found

in this study.


Conclusion:


This feasibility study failed to show any change in muscle strength and joint laxity

and consequently no relationship between either of these parameters across the

MC. However, it is clear from the literature that individually muscle strength and

joint laxity may be dependent on sex hormones in women. Due to the high

variability in women, further research is required with more distinguishable

phases of the cycle determined by hormone analysis, more accurate

measurement techniques and comparisons made on an individual basis

compared to a CSA.




                                        21
Acknowledgements:


I would like to thank the students who took part in this study. I am also very

grateful to Melanie Wright for her help with the statistical data, and Rebecca

Morrision for being my supervisor.




                                         22
References:

     Bambaeichi, E., Reilly,T., Cable and Giacomoni, M. (2004). The Isolated
      and Combined Effects of Menstrual Cycle Phase and Time-of-Day on
      Muscle Strength of Eumenorrheic Females. Chronobiology International,
      21(4-5), 645-660.


     Davies, B.N., Elford, J.C.C. and Jamieson, K.F. (1991). Variations in
      performance in simple muscle tests at different phases of the menstrual
      cycle. The Journal of Sports Medicine and Physical Fitness, 31, 532-7.


     Deie, M., Sakamaki, Y., Sumen, Y., Urabe, Y., Ikuta, Y. (2002). Anterior
      knee laxity in young women varies with their menstrual cycle. Int Orthop,
      26(3), 154-6.


     De Souza, M.J., Miller, B.E., Loucks, A.B., Luciano, A.A., Pescatello, L.S.,
      Campbell, C.G. and Lasley, B.L. (1998). High frequency of luteal phase
      deficiency and anovulation in recreational women runners: blunted
      elevation in follicule-stimulating hormone observed during luteal-follicular
      transition. Journal of Clinical Endocrinology and Metabolism, 83, 4220-
      4232.


     Dibrezzo, R.O., Fort, I.L. and Brown, B. (1991). Relationship among
      strength, endurance, weight and body fat during three phases of the
      menstrual cycle. The Journal of Sports Medicine and Physical Fitness,
      31(1), 89-94.


     Friden, C., Hirschbreg, A.L., Saartok, T. (2003). Muscle strength and
      endurance do not significantly vary across phases of the menstrual cycle
      in moderately active premenopausal women. Clinical Journal Sport
      Medicine, 13(4), 238-41.
                                        23
   Hertel, J., Williams, N.I., Olmsted-Kramer, L.C., Leidy, H.J. and Putukian,
    M. (2006). Neuromuscular performance and knee laxity do not change
    across the menstrual cycle in female athletes. Knee Surg Sports
    Traumatol Arthrosc, 14, 817-822.



   Heitz, N.A., Eisenman, P.A., Beck, C.L. and Walker, J.A. (1999).
    Hormonal changes throughout the menstrual cycle and increased anterior
    crucitate ligament laxity in females. Journal of Athletic training, 34(2), 144-
    149.




   Janse de Jonge, X.A.K., Boot, C.R.L., Thom, J.M., Ruell, P.A. and
    Thompson, M.W. (2001). The influence of menstrual cycle phase on
    skeletal muscle contractile characteristics in humans. Journal of
    Physiology, 530(1), 161-166.



   Jobbins, B., Bird, H.A. and Wright, V (1979). A joint hyperextensometer for
    the quantification of joint laxity. I Mech E, 8(2), 103-4.



   Kubo, K., Miyamoto, M., Tanaka, S., Maki, A., Tsunoda, N. and Kanehisa,
    H. (2009) Muscle and tendon properties during menstrual cycle.
    International Journal Sports Medicine, 30(2), 139-43.



   Karageanes, S.J., Blackburn, K., Vangelos, Z.A. (2000). The association
    of the menstrual cycle with the laxity of the anterior cruciate ligament in
    adolescent female athletes. Clinical J Sport Med, 10, 162-8.


                                       24
   Lebrun, C.M., McKenzie, D.C., Prior, J.C., Taunton, J.E. (1995). Effects of
    menstrual cycle phase on athletic performance. Med Sci Sports Exerc,
    27(3), 437-444.



   Lunen, B.L.V., Roberts, J., Branch, J.D. and Dowling, E.A. (2003).
    Association of menstrual cycle hormone changes with anterior cruciate
    ligament laxity measurements. Journal of Athletic Training, 38(4), 298-303.



   Montgomery, M.M. and Shultz, S.J. (2010) Isometric knee-extension and
    knee-flexion torque production during early follicular and postovulatory
    phases in recreationally active women. Journal of Athletic Training, 45(6),
    586-93



   Phillips, S.K., Gopinathan, K., Meehan, K., Bruce, S.A., Woledge, R.C.
    (1993). Muscle strength changes during the menstrual cycle in human
    adductor policis. Journal of physiology, 473, 125.



   Phillips, S.K., Sanderson, A.G., Birch, K., Bruce, S.A. and Woledge, R.C.
    (1996). Changes in maximal voluntary force of human adductor pollicis
    muscle during the menstrual cycle. Journal of Physiology, 496(2), 551-
    557.



   Reis, E., Frick, U., Schmidtbleicher, D. (1995). Frequency variations of
    strength training sessions triggered by the phases of the menstrual cycle.
    Int J Sports Med, 8, 545-50.




                                     25
   Sandler, S.E. (2006). Changes in joint laxity associated with the menstrual
    cycle, with pregnancy, with the post partum period and with the
    menopause. British School of Osteopathy, London.



   Sarwar, R., Niclos, B.B. and Rutherford, O.M. (1996). Changes in muscle
    strength, relaxation rate and fatigability during the human menstrual cycle.
    J physiol, 15(493), 267-72.



   Shultz, S.J., Kirk, S.E., Johnson, M.L., Sander, T.C. and Perrin, D.H.
    (2004). Relationship between sex hormones and anterior knee laxity
    across the menstrual cycle. Med Sci Sports Exerc, 36(7).



   Shultz, S.J., Sander, T.C., Kirk, S.E. and Perrin, D.H. (2005). Sex
    difference in knee joint laxity change across the female menstrual cycle. J
    Sports Med Phys Fitness, 45(4), 594-603.


   Slauterbeck, J.R., Fuzie, S.F., Smith, M.P., Clark, R.J., Xu, K.T., Stratch,
    D.W. and Hardy, D.M. (2002). The menstrual cycle, sex hormones and
    anterior cruciate ligament injury. Journal of Athletic Training, 37(3), 275-
    280.




                                      26
Appendix 1:

Dear colleagues,

I am a fourth year student doing a study on the effects of the menstrual cycle on
muscle strength and joint laxity and currently recruiting participants and would be
very grateful if you would consider taking part.

I'm hoping to recruit 20 female BSO students who fall under the following
categories:

- Currently NOT on any oral contraceptives or any other hormone preparation for
at least the last 3 months
- Has a regular and predictable menstrual cycle of between 28-32 days
- No history of inflammatory joint disease, arthritis
- No history of being diagnosed with hyper mobility, joint laxity or have a current
injury to your dominant hand or arm.

The project will involve being measured at 3 specific times over one month. The
measurement involves you having the index finger of your dominant hand
measured for joint looseness. It is a painless procedure which takes a few
seconds. The measurements also include performing a muscle test in which you
are asked to measure your hand grip strength. This involves squeezing as hard
as possible on a hand held piece of equipment for 5 seconds. These
measurements will help the researcher see if there
is a change in the looseness of the finger joint and changes in muscle strength,
which correspond with the different phases of the menstrual cycle.

Participants will be tested on one of the days falling during each of the three
phases of their cycle. Menstrual phase (days 1-4), follicular phase (days 12-14)
and luteal phase (days 19-21). Therefore giving lee-way of 4 days for each
phase. This information will be given to the participants for them to work out
which days to come for testing, so confidentiality regarding their menstrual cycle
is maintained.

Each measurement session will take approximately 20 minutes and will take
place in an allocated room at the British School of Osteopathy and will be
scheduled at a time suitable for the participant.

There are minimal risks involved in this study, mainly related to the muscle
strength test, in which you will need to grip the testing equipment as strongly as
you can for a few seconds. The joint mobility testing procedures are painless and
will not cause any harm. Harm will only occur if the participant does not follow the
instructions given to them during the measurements however this will avoided by
using clear explanations. Insurance will be covered by the British School of
Osteopathy.
                                         27
Although there is no direct benefit to taking part, it is hoped the findings of the
study will help provide osteopaths and other healthcare practitioners with more
knowledge to help treat and manage physically active females in their
reproductive years.

If participants feel any discomfort during the experiment, they can withdraw at
any time, without giving reasons. In the unlikely event that anyone feels harmed
or has a complaint, they will be advised to contact the supervisor for advice and
support.

All information collected about participants will be kept strictly confidential and all
participants will be assigned numbers, so that no names will be on the data
sheet. The researcher will be the only one who has access to the names of the
participants involved in the study. The supervisor will have access to the data
collected however will be unaware of the actual names of the participants
involved. All data will be kept securely at the British School of Osteopathy during
the project and destroyed 6 years following completion of the study. All names
and other identifiable information will be omitted from the written paper.

The results of the study will be analysed and written up as a final research paper,
which will be available in the BSO library after July 2011. If you would like a
summary of the results after July 2011, please contact me at the email address
below.

My name is Juliette Taylor and I am the principal researcher. My supervisor is
Rebecca Morrison, a BSO member of staff. Our contact details are given below
should you have questions or want further information. Thank you for taking the
time to read this information sheet.

So if this study appeals to you and you fall into the inclusion catergory please
contact me either by email juliette.taylor@bso.ac.uk or
juliette_taylor@hotmail.com.


Attached is my participation sheet for the proposed study. If you have any
questions don't hesitate to ask.

Many thanks for your time.

Juliette Taylor




                                          28
Appendix 2:

CONFIDENTIAL


Participant Identification Number:


                                     CONSENT FORM


Title of Project: Effects of menstrual cycle on joint laxity and muscle strength



Name of Researcher: Juliette Taylor

Name of Supervisor: Rebecca Morrison



                                                        Please tick where appropriate

1.     I confirm that I have read the information sheet for the              
       above study and have had the opportunity to ask questions

2.     I understand that my participation is voluntary and that I            
       am free to withdraw at any time, without giving any reason

3.     I agree to take part in the above study                               

4.     I would like to receive a summary of the results                      

5.     Please send a summary of the result to ……………………………………..


Name of the Participant                      Date                     Signature



Researcher                                   Date                     Signature



1 copy for the researcher: 1 copy for the participant

                                            29
Appendix 3:
                                  Participant Information Sheet
Study Title - The effects of the menstrual cycle on muscle strength and joint laxity.

Invitation paragraph
We would like to invite you to take part in our undergraduate degree research study. Before you
decide we would like you to understand why the research is being done and what it would involve
for you. The researcher will go through the information sheet with you and answer any questions
you have. We‘d suggest this should take about 10 minutes. Talk to others about the study if you
wish. Ask us if there is anything that is not clear.

What is the purpose of the study?
The aim of this project is to investigate whether there is a significant change in joint laxity and
muscle strength throughout the different phases of the menstrual cycle. There are three main
stages of the menstrual cycle; menstrual phase (days 1-4), follicular phase (days 12-14) and
luteal phase (days 19-21). The purpose is to gain knowledge for osteopaths and other healthcare
practitioners about the potential links between the events in the menstrual cycle with change in
muscle strength and joint laxity, to aid awareness in adapting their approach to diagnosis,
treatment and management when treating physically active females in their reproductive years.

Why have I been invited?
All female students at British School of Osteopathy have been invited to take part in this study.
The researcher aims to recruit approximately 20 female students.

Do I have to take part?
It is up to you to decide to join the study. We will describe the study and go through this
information sheet. If you agree to take part, we will then ask you to sign a consent form. You are
free to withdraw at any time, without giving a reason. Whether you decide to take part, or not, will
not affect your standing as a student at the BSO and you can also withdraw at any time without
penalty.

What will happen to me if I take part?
The project will involve being measured at specific times over one month. The measurement
involves you having the index finger of your dominant hand measured for joint looseness. It is a
painless procedure which takes a few seconds. The measurements also include performing a
muscle test in which you are asked to measure your hand grip strength. This involves squeezing
as hard as possible on a hand held piece of equipment for 5 seconds. These measurements will
help the researcher see if there is a change in the looseness of the finger joint and changes in
muscle strength, which correspond with the different phases of the menstrual cycle.

What do I have to do?
Female participants will need to have regular and predictable menstrual cycle of 28-32 days and
also currently not be taking any oral contraceptive pill or hormone replacement, for at least the
last three months. Participant will be tested on one of the days falling during each of the three
phases of their cycle. Menstrual phase (days 1-4), follicular phase (days 12-14) and luteal phase
(days 19-21). This information will be given to the participants for them to work out which days to
come for testing, so confidentiality regarding their menstrual cycle is maintained.
Each measurement session will take approximately 20 minutes and will take place in an allocated
room at the British School of Osteopathy.

Inclusion Criteria:
You are eligible to take part if you are female BSO students, aged between 18 and 45, who has a
regular menstrual cycle of 28-32 days (from first of menstruating to first day of menstruating of
following menstrual cycle).

                                                 30
Women with disabilities are eligible to take part in the study as long as they are able to perform
the hand grip test.
It is also important that you have not used oral contraceptives or any other hormone preparation
for at least three months prior to testing, to ensure that fluctuations of hormones have not been
pharmacologically effected.

Exclusion Criteria:
You will not be able to participate if you have a history of inflammatory joint disease, arthritis, or
trauma to your hand and dominant index finger, as the tests may cause injury or pain. You will
also not be able to take part if you have been diagnosed with hyper-mobility, joint laxity or have a
current injury to your dominant hand or arm.

What are the possible disadvantages and risks of taking part?
There are minimal risks involved in this study, mainly related to the muscle strength test, in which
you will need to grip the testing equipment as strongly as you can for a few seconds. The joint
mobility testing procedures are painless and will not cause any harm. Harm will only occur if the
participant does not follow the instructions given to them during the measurements however this
will avoided by using clear explanations. Insurance will be covered by the British School of
Osteopathy.

What are the possible benefits of taking part?
Although there is no direct benefit to taking part, it is hoped the findings of the study will help
provide osteopaths and other healthcare practitioners with more knowledge to help treat and
manage physically active females in their reproductive years.

What if there is a problem?
If participants feel any discomfort during the experiment, they can withdraw at any time, without
giving reasons. In the unlikely event that anyone feels harmed or has a complaint, they will be
advised to contact the supervisor for advice and support.

Will my taking part in the study remain confidential?
All information collected about participants will be kept strictly confidential and all participants will
be assigned numbers, so that no names will be on the data sheet. The researcher will be the only
one who has access to the names of the participants involved in the study. The supervisor will
have access to the data collected however will be unaware of the actual names of the participants
involved. All data will be kept securely at the British School of Osteopathy during the project and
destroyed 6 years following completion of the study. All names and other identifiable information
will be omitted from the written paper.

What will happen to the results from the study?
The results of the study will be analysed and written up as a final research paper, which will be
available in the BSO library after July 2011. If you would like a summary of the results after July
2011, please contact me at the email address below.

Who is organising the research?
My name is Juliette Taylor and I am the principal researcher. My supervisor is Rebecca Morrison,
a BSO member of staff. Our contact details are given below should you have questions or want
further information. Thank you for taking the time to read this information sheet.

Researcher: Juliette Taylor                         Supervisor: Rebecca Morrison
British School of Osteopathy                        British School of Osteopathy
275 Borough High Street                             275 Borough High Street
London SE1 1JE                                      London SE1 1JE
Email: Juliette.taylor@bso.ac.uk                    Email: r.morrison@bso.ac.uk
Contact no: 0207 407 0222                           Contact no: 0207 089 5345
                                                   31
Appendix 4:

                                Participant Information Sheet
                                         Pilot Study

Study Title - The effects of the menstrual cycle on muscle strength and joint laxity.

Invitation paragraph
We would like to invite you to take part in our undergraduate degree pilot study. Before you
decide we would like you to understand why the research is being done and what it would involve
for you. The researcher will go through the information sheet with you and answer any questions
you have. We‘d suggest this should take about 10 minutes. Talk to others about the study if you
wish. Ask us if there is anything that is not clear.

What is the purpose of the pilot study?
The aim of this project is to investigate whether there is a significant change in joint laxity and
muscle strength throughout the different phases of the menstrual cycle. The purpose of the pilot
study is to test the experiment procedure before the main experiment is undertaken.

What is the purpose of the study?
The purpose is to gain knowledge for osteopaths and other healthcare practitioners about the
potential links between the events in the menstrual cycle with change in muscle strength and joint
laxity, to aid awareness in adapting their approach to diagnosis, treatment and management
when treating physically active females in their reproductive years.

Why have I been invited?
All female students at British School of Osteopathy have been invited to take part in this study.
The researcher aims to recruit 5 female students or members of staff for the pilot study.

Do I have to take part?
It is up to you to decide to join the pilot study. We will describe the study and go through this
information sheet. If you agree to take part, we will then ask you to sign a consent form. You are
free to withdraw at any time, without giving a reason. Whether you decide to take part, or not, will
not affect your standing as a student at the BSO and you can also withdraw at any time without
penalty.

What will happen to me if I take part?
The project will involve being measured on one occasion. The measurement involves you having
the index finger of your dominant hand measured for joint looseness. It is a painless procedure
which takes a few seconds. The measurements also include performing a muscle test in which
you are asked to measure your hand grip strength. This involves squeezing as hard as possible
on a hand held piece of equipment for 5 seconds. The procedure will be performed three times
per test by the researcher and then again with the supervisor. These measurements will help the
researcher see if the data can be taken consistently and to conclude that valid data can be
collected regardless of the assessor.

What do I have to do?
                                                                                th  th
Participant will be tested on one occasion that suits them between the dates; 20 -30 September
2010. The session will take approximately 20-30 minutes and will take place in an allocated room
at the British School of Osteopathy.

Inclusion Criteria:
You are eligible to take part if you are female BSO students or faculty.

                                                 32
Women with disabilities are eligible to take part in the study as long as they are able to perform
the hand grip test.

Exclusion Criteria:
You will not be able to participate if you have a history of inflammatory joint disease, arthritis, or
trauma to your hand and dominant index finger, as the tests may cause injury or pain. You will
also not be able to take part if you have been diagnosed with hyper-mobility, joint laxity or have a
current injury to your dominant hand or arm.

What are the possible disadvantages and risks of taking part?
There are minimal risks involved in this study, mainly related to the muscle strength test, in which
you will need to grip the testing equipment as strongly as you can for a few seconds. The joint
mobility testing procedures are painless and will not cause any harm. Harm will only occur if the
participant does not follow the instructions given to them during the measurements however this
will avoided by using clear explanations. Insurance will be covered by the British School of
Osteopathy.

What are the possible benefits of taking part?
Although there is no direct benefit to taking part, the pilot study will help the researcher test
adequacy of the research equipment, identify logistical problems which might occur using the
proposed methods and train the researcher in as many elements of the research process as
possible.

What if there is a problem?
If participants feel any discomfort during the experiment, they can withdraw at any time, without
giving reasons. In the unlikely event that anyone feels harmed or has a complaint, they will be
advised to contact the supervisor for advice and support.

Will my taking part in the study remain confidential?
All information collected about participants will be kept strictly confidential and all participants will
be assigned numbers, so that no names will be on the data sheet. The researcher and supervisor
will be the only one who has access to the names of the participants involved in the study. All
data will be kept securely at the British School of Osteopathy during the project and destroyed 6
years following completion of the study.

What will happen to the results from the pilot study?
As the results are collected for the purpose of testing the experimental procedure the data
collected will not be used in the main study. Results will be tested for central tendency and then
compared between researcher and supervisor to evaluate whether data can be collected
consistently and independent of the assessor.

Who is organising the research?
My name is Juliette Taylor and I am the principal researcher. My supervisor is Rebecca Morrison,
a BSO member of staff. Our contact details are given below should you have questions or want
further information. Thank you for taking the time to read this information sheet.

Researcher: Juliette Taylor                         Supervisor: Rebecca Morrison
British School of Osteopathy                        British School of Osteopathy
275 Borough High Street                             275 Borough High Street
London SE1 1JE                                      London SE1 1JE
Email: Juliette.taylor@bso.ac.uk                    Email: r.morrison@bso.ac.uk
Contact no: 0207 407 0222                           Contact no: 0207 089 5345



                                                   33

				
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