During the RTD task, subjects were instructed to perform 5-10 isometricontractionsns, with each contraction performed as quickly and forcefully as possible, but without holding the contraction at maximal torque; the peak torque per unit time (N·m/s) was recorded and calculated offline as the linear slope of the torque-time curve from 10-90% of the fast contractions.
The global torsional stiffness (Nm/deg) was calculated from the slope of the torque-rotational angle response.
As a consequence, the linear regression slope of the torque-pedalling rate was similar (−1.040 versus −1.035) in the field and laboratory tests.
Moreover, reductions in the slope of the torque-angular position curve were associated with improved hamstring extensibility following 4-weeks of passive stretching in healthy young men and women [ 12].
In contrast increased passive hamstring stiffness, quantified as the slope of the torque-angular position curve during passive hip flexion, was observed to significantly predict decreased extensibility in both healthy individuals and patients with chronic LBP [ 5].
For tetanic contractions, the Fatigue Index (ratio of peak torque values) and the slope of the regression line of peak torque values were primary outcome measures.
A positive slope of the torque signal before onset of torque development indicated that the knee extensors were not fully relaxed prior to torque onset (pre-tension), which in previous studies was confirmed by very low levels of knee extensor EMG activity (de Ruiter et al. 2004a, b).
Although Parkinsonian subjects had smaller torques, the slope of their postural response magnitude scaling to displacement velocity was normal.
Rate of torque development (RTD) was obtained by the slope of the isometric contraction torque-time curve (i.e., Δtorque ·Δtime−1) across the time intervals of 0 30, 0 50, 0 100, 0 150, 0 200, and 0 250 ms relative to the onset of contraction.
When interpreting fatigue-induced changes in rapid muscle torque production characteristics and neuromuscular activity in response to match-play tennis in HOT and COOL conditions, alterations in the contractile rates of torque development should be analysed using peak slope values and those obtained in the late phase (>100 ms) of the rising muscle contraction.
