Effects of Androgen Deprivation on Functional Mobility in Men Assessed by Three-Dimensional Gait Analysis Combined with Musculoskeletal Computer Modelling

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 524-553-Male Reproductive Endocrinology
Bench to Bedside
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-541
Ada S Cheung1, Anthony Schache2, Hans Gray2, Philippe Dupuis1, Daryl Lim Joon3, Jeffrey D Zajac1, Marcus Pandy2 and Mathis Grossmann*1
1University of Melbourne Austin Health, 2Dept. of Mechanical Engineering, University of Melbourne, 3Radiation Oncology Austin Health
Context: While testosterone is important for maintenance of muscle mass and strength in ageing men, its role in physical performance is less well defined.

Objective: To assess the effects of androgen withdrawal on functional mobility, using a novel approach combining detailed gait analyses with computational musculoskeletal modelling (1).

Methods: We conducted a longitudinal observational study in men with non-metastatic prostate cancer receiving continous androgen deprivation therapy (ADT) adjuvant to radiotherapy. Men receiving radiotherapy without ADT served as controls. Participants underwent quantitative gait analyses (involving level ground walking and stair ambulation) at baseline (prior to ADT initiation) and at 6 and 12 months. Gait analysis was performed on each subject to measure three-dimensional (3D) joint motion, ground reaction forces, and muscle activation patterns. Musculoskeletal computer modelling then was used to calculate lower-limb muscle forces and determine individual muscle contributions to three key biomechanical functions during walking: vertical support, forward progression, and mediolateral (sideways) balance.

Results: Here we report preliminary results in 11 men receiving ADT, age 68±7.8 years, baseline total testosterone 13.14 ± 5.93 nmol/L. Compared to baseline, 12 months of ADT was associated with significant reductions in the net muscle torques developed about the hip and knee joints (p = 0.0001 for hip and p = 0.001 for knee). In addition, grip strength decreased and frailty score increased (p<0.01). Twelve months of ADT was also associated with significantly (p < 0.05) reduced peak forces developed by the iliopsoas (iliacus p =0.0001and psoas p =0.0003) and the quadriceps muscles (rectus femoris p =0.0005, vastus medialis p =0.0014, v. intermedius p =0.0032, p. lateralis p =0.002). The quadriceps generated less support and iliopsoas’ contributions to mediolateral balance was reduced. In contrast, gluteus maximus increased its contributions to both forward progression and mediolateral balance. No significant changes were observed in the behaviour of the other lower-limb muscles.

Conclusions: Our preliminary results indicate that gait modifications are evident in patients receiving 12 months of ADT treatment. Perhaps the most conspicuous change observed was the propensity of gluteus maximus to compensate for the reduced contributions of quadriceps and iliopsoas to support and balance, respectively. Further analyses with larger sample numbers are needed to confirm the validity of this finding. Quantitative 3D gait analysis when combined with musculoskeletal computer modelling is a potentially powerful tool for evaluating the efficacy of pro-myogenic interventions.

(1) Seth, A. & Pandy, M.G. (2007) A neuromusculoskeletal tracking method for estimating individual muscle forces in human movement. J Biomech 40, 356-366.

Nothing to Disclose: ASC, AS, HG, PD, DL, JDZ, MP, MG

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: This work was supported by  grants from the National Health and Medical Research Council of Australia (Project Grant #1006407, Career Development Fellowship to M.G. #1024139).