text: Muscle strength is impaired in men but not in women living with HIV taking antiretroviral therapy.
  There is evidence that HIV antiretroviral therapy adverse effects may be sex-dependent, but data examining these sex differences in muscle strength is scarce. Our aim was to compare dynamic and isokinetic parameters of muscle strength between HIV-infected men and women to HIV-uninfected subjects. In this cross-sectional study, muscle strength was evaluated in 44 HIV-infected (20 men, 24 women) and 25 age-, race- and body mass index-matched HIV-uninfected subjects (11 men, 14 women). We assessed knee flexion and extension efforts in isokinetic dynamometer at angular velocities of 60° and 180°/s, and 1 repetition maximum test (1RM) for bench press, leg press and arm curl exercises, respectively. Lean body mass (LBM) was measured using bioelectrical impedance. HIV-infected men had significantly less dynamic muscle strength for 1RM total (262.5 versus 357.2 kg), bench press (48.6 versus 60.3 kg), leg press (182.7 versus 261 kg) and arm curl (31.2 versus 36.5 kg) compared to HIV-uninfected men (P≤0.05); no differences were found among women. Men had lower values for peak torque in extension and flexion movements at 60°/s and 180°/s, while HIV-infected women presented higher peak torque in extension movement at 60°/s compared to controls. No differences were found in LBM. Moreover, isokinetic evaluation demonstrated that HIV-infected subjects showed greater acceleration and deceleration time in some variables, compared to controls, related to difficulty in activating motor units. HIV infection is associated with impaired dynamic and isokinetic strength in men compared to HIV-uninfected controls, but not in women.