Biomechanical leg muscle function during stair ambulation in men receiving androgen deprivation therapy.

Abstract

The role of testosterone in maintaining functional performance in older men remains uncertain. We conducted a 12-month prospective, observational case-control study including 34 men newly commencing androgen deprivation therapy (ADT) for prostate cancer and 29 age-matched prostate cancer controls. Video-based motion capture and ground reaction force data combined with computational musculoskeletal modelling, and data were analysed with a linear mixed model. Compared to controls over 12 months, men receiving ADT had a mean reduction in circulating testosterone from 14.1nmol/L to 0.4nmol/L, associated with reductions in peak knee extension torque, mean adjusted difference (MAD) -0.07 Nm/kg [95%CI -0.18, 0.04], p=0.009, with a corresponding more marked decrease in quadriceps force MAD -0.11 x body weight (BW) [-0.27, 0.06], p=0.045 (equating to a 9 kg force reduction for the mean BW of 85 kg), and decreased maximal contribution of quadriceps to upward propulsion, MAD -0.47 m/s2 [-0.95, 0.02], p=0.009. We observed between group differences in several other parameters, including increased gluteus maximus force in men receiving ADT, MAD 0.11xBW [0.02, 0.20], p=0.043, which may be compensatory. Severe testosterone deprivation over 12 months is associated with selective deficits in lower limb function evident with an important task of daily living.