The “gold standard” for measuring peak muscle power outputs is a comprehensive torque-velocity assessment performed across a wide range of loads and contraction velocities. However, this approach requires multiple high-load efforts that place stress on the joints, is time-intensive, and is often impractical in large cohorts or in clinical populations such as very old adults. Further, it remains unclear whether simplified protocols underestimate age- and sex-related differences in peak power. We compared peak knee extensor power derived from a torque-velocity assessment with that obtained from the initial 10 contractions of a single-load fatiguing task in young, old, and very old males and females. Thirty young (22.6±2.2 yrs, 15 females), 73 old (70.6±4.7 yrs, 33 females), and 16 very old adults (85.8±4.2 yrs, 9 females) completed a torque-velocity assessment (14 isokinetic velocities, 30-450°·s -1 ) and a 4-min dynamic fatiguing exercise task (1 isotonic load at 20% of maximal voluntary isometric contraction, 80 contractions). Peak power outputs were strongly correlated between protocols ( p<.001, r=0.962), and the estimated age-related declines in power did not differ between the torque-velocity and fatigue task in males (~6.6 W·yr -1 vs. ~6.5 W·yr -1 , p=0.639) or females (~4.3 W·yr -1 vs. ~4.2 W·yr -1 , p=0.736). Peak power outputs from the initial 10 contractions of the fatigue task were ~13% lower compared with the torque-velocity assessment ( p<0.001). These findings indicate that a brief fatiguing exercise task provides a valid alternative to the torque-velocity assessment for determining peak power across age groups, while simultaneously measuring fatigability, a clinically and physiologically important neuromuscular characteristic.
Wrucke et al. (Thu,) studied this question.