Fig. 6.

Photograph and baseline-torque recordings from a commercial isokinetic dynamometer (a, c) and a custom-built dynamometer (b, d), measuring knee extensor torque at ~60° knee flexion in the same participant. The padding on the chair/crank-arm adaptor in a, that is not present in b, contributes to dynamometer compliance. Torque in d is the product of force and moment arm. The baseline-torque recordings in c and d are prior to and during the early phase of an explosive contraction, and presented in the same scale for both absolute (Nm) and relative (% MVC) units. The dashed lines are ±3 SDs of the baseline mean which is often used as a threshold for detecting contraction onset, and is comparable with typical objective criteria thresholds for detecting an unstable baseline (e.g., shift above/below this threshold in the preceding 200 ms). The considerably greater baseline noise amplitude in c makes the thresholds for detecting contraction onset and/or an unstable baseline, including any pre-tension or countermovement, markedly less sensitive than in d