Matthias Stettler

Isometric rate of force development, maximum voluntary contraction, and balance in women with and without joint hypermobility.

OBJECTIVE To determine differences between hypermobile subjects and controls in terms of maximum strength, rate of force development, and balance. METHODS We recruited 13 subjects with hypermobility and 18 controls. Rate of force development and maximal voluntary contraction (MVC) during single leg knee extension of the right knee were measured isometrically for each subject. Balance was tested twice on a force plate with 15-second single-leg stands on the right leg. Rate of force development (N/second) and MVC (N) were extracted from the force-time curve as maximal rate of force development (= limit Deltaforce/Deltatime) and the absolute maximal value, respectively. RESULTS The hypermobile subjects showed a significantly higher value for rate of force development (15.2% higher; P = 0.038, P = 0.453, epsilon = 0.693) and rate of force development related to body weight (16.4% higher; P = 0.018, P = 0.601, epsilon = 0.834) than the controls. The groups did not differ significantly in MVC (P = 0.767, P = 0.136, epsilon = 0.065), and MVC related to body weight varied randomly between the groups (P = 0.921, P = 0.050, epsilon = 0.000). In balance testing, the mediolateral sway of the hypermobile subjects showed significantly higher values (11.6% higher; P = 0.034, P = 0.050, epsilon = 0.000) than that of controls, but there was no significant difference (4.9% difference; P = 0.953, P = 0.050, epsilon = 0.000) in anteroposterior sway between the 2 groups. CONCLUSION Hypermobile women without acute symptoms or limitations in activities of daily life have a higher rate of force development in the knee extensors and a higher mediolateral sway than controls with normal joint mobility.

Neuromechanical gait adaptations in women with joint hypermobility —An exploratory study

BACKGROUND Joint hypermobility is known to be associated with joint and muscle pain, joint instability and osteoarthritis. Previous work suggested that those individuals present an altered neuromuscular behavior during activities such as level walking. Therefore, the aim of this study was to explore the differences in ground reaction forces, temporal parameters and muscle activation patterns during gait between normomobile and hypermobile women, including symptomatic and asymptomatic hypermobile individuals. METHODS A total of 195 women were included in this cross-sectional study, including 67 normomobile (mean 24.8 [SD 5.4] years) and 128 hypermobile (mean 25.8 [SD 5.4] years), of which 56 were further classified as symptomatic and 47 as asymptomatic. The remaining 25 subjects could not be further classified. Ground reaction forces and muscle activation from six leg muscles were measured while the subjects walked at a self-selected speed on an instrumented walkway. Temporal parameters were derived from ground reaction forces and a foot accelerometer. The normomobile and hypermobile groups were compared using independent samples t-tests, whereas the normomobile, symptomatic and asymptomatic hypermobile groups were compared using one-way ANOVAs with Tukey post-hoc tests (significance level=0.05). FINDINGS Swing phase duration was higher among hypermobile (P=0.005) and symptomatic hypermobile (P=0.018) compared to normomobile women. The vastus medialis (P=0.049) and lateralis (P=0.030) and medial gastrocnemius (P=0.011) muscles showed higher mean activation levels during stance in the hypermobile compared to the normomobile group. INTERPRETATION Hypermobile women might alter their gait pattern in order to stabilize their knee joint.

Stair climbing – An insight and comparison between women with and without joint hypermobility: A descriptive study

Generalized joint hypermobility (GJH) is a frequent entity in rheumatology with higher prevalence among women. It is associated with chronic widespread pain, joint dislocations, arthralgia, fibromyalgia and early osteoarthritis. Stair climbing is an important functional task and can induce symptoms in hypermobile persons. The aim of this study was to compare ground reaction forces (GRF) and muscle activity during stair climbing in women with and without GJH. A cross-sectional study of 67 women with normal mobility and 128 hypermobile women was performed. The hypermobile women were further divided into 56 symptomatic and 47 asymptomatic. GRFs were measured by force plates embedded in a six step staircase, as well as surface electromyography (EMG) of six leg muscles. Parameters derived from GRF and EMG were compared between groups using t-test and ANOVA. For GRF no significant differences were found. EMG showed lower activity for the quadriceps during ascent and lower activity for hamstrings and quadriceps during descent in hypermobile women. For symptomatic hypermobile women these differences were even more accentuated. The differences in EMG may point towards an altered movement pattern during stair climbing, aimed at avoiding high muscle activation. However, differences were small, since stair climbing seems to be not demanding.

Passive anterior tibial translation in women with and without joint hypermobility: an exploratory study.

Generalized joint hypermobility (GJH) is a frequent entity, which is still not fully understood. Symptoms associated with GJH are musculoskeletal disorders, decreased balance, impaired proprioception and chronic pain. The purpose of this study was to compare the passive anterior tibial translation (TT) in terms of distance and corresponding force between normomobile (NM) and hypermobile (HM) as well as between NM, symptomatic (HM‐s) and asymptomatic (HM‐as) hypermobile women.

THU0622-HPR Discriminating Conditional and Functional Factors for Women with and Without Hypermobility – an Observational Study

Background Generalized joint hypermobility (GJH) is often seen and widely underestimated regarding complexity of diagnosis and treatment. The prevalence of GJH was reported between 10% and 18%, with women more often affected (1). Diagnosis is mainly based on the Beighton score (BS), which is based on increased range of motion (ROM) in specific joints like knee, elbow and fingers (2). However, little is known about the importance of conditional factors like muscle strength or balance in persons with GJH, and their influence on pain and disability. Objectives Aim of this study was to find factors discriminating between hypermobile women with and without symptoms, and women with normal mobility. Methods A total of 195 women (mean age 25.5 years) were included in this cross-sectional study, whereby 67 were normomobile, 56 symptomatically hypermobile and 47 asymptomatically hypermobile. Hypermobile women had BS of 6 or higher and classification according to symptoms was based on self-reported pain during 6 months. Measurements comprised passive anterior translation of the tibia, passive ROM of the knees, BS, muscle strength, balance during single-leg standing, as well as muscle activity (MA) and ground reaction forces (GRF) during gait and stair climbing. The main parameters of every measurement were included in a principle component analysis (PCA) and all factors with eigenvalue>1 were extracted (3). Main components of these factors were derived from the variables to describe possible discriminating factors between groups. Results 17 principle components showed eigenvalue>1 and were included in further analysis. Together they accounted for 80% of variance between groups. The five most important factors (eigenvalue>3) accounted for 46% of variance. These factors were composed as follows: #1 (13.7% of variance) consisted of GRF parameters during gait and on stair, #2 (11.0%) was balance as well as quadriceps and hamstrings MA during gait and on stair, #3 (8.4%) included strength of knee extensors and balance, #4 (6.2%) was composed of MA of lower leg muscles on stair, strength of knee flexors, body weight and BMI and #5 (5.7%) was based on passive ROM of knee, BS and passive tibial translation. Conclusions PCA could not reduce the variables on few factors. Contrariwise, 17 factors remained and the five most important could explain less than 50% of the variance between groups. Furthermore, yet these five factors consisted of several variables derived from different measurements. In general MA was not very important and passive ROM occurred not before factor #5, as well as BS. The high number of extracted factors might be a sign of the complex nature of hypermobility. BS and passive ROM seemed not to be the primary factors to discriminate between women with hypermobility and with normal mobility. The measurements were probably not enough demanding for young women to clearly discriminate symptomatic hypermobile women from asymptomatic hypermobile women. References Simmonds & Keer, Manual Therapy. 2007:298-309. Remvig et al. The Journal of Rheumatology. 2007:798-803. Field: Discovering Statistics using SPSS, London, 2013. Acknowledgements The project was supported by the Swiss National Science Foundation (# 13DPD6 127285) and approved by the Ethics Committee of Canton Bern, Switzerland (Number 229/2008). Disclosure of Interest None declared