Downhill running affects the late but not the early phase of the rate of force development

Abstract

Purpose This study aimed to evaluate the acute changes in the knee extensors maximum voluntary isometric contraction force (MVIC), rate of force development (RFD), and rate of EMG rise (RER) following a bout of downhill running. Methods MVIC and RFD at 0–50, 50–100, 100–200, and 0–200 ms were determined in thirteen men (22 ± 2 yr) before and after 30 min of downhill running (speed: 10 km h−1; slope: − 20%). Vastus lateralis maximum EMG (EMGmax) and RER at 0–30, 0–50, and 0–75 ms were also recorded. Results MVIC, RFD0–200, and EMGmax decreased by ~ 25% [Cohen’s d = − 1.09 (95% confidence interval: − 1.88/− 0.24)], ~ 15% [d = − 0.50 (− 1.26/0.30)], and ~ 22% [d = − 0.37 (− 1.13/0.42)] (all P < 0.05), respectively. RFD100–200 was also reduced [− 25%; d = − 0.70 (− 1.47/0.11); P < 0.001]. No change was observed at 0–50 ms and 50–100 ms (P ≥ 0.05). RER values were similar at each time interval (all P > 0.05). Conclusion Downhill running impairs the muscle capacity to produce maximum force and the overall ability to rapidly develop force. No change was observed for the early phase of the RFD and the absolute RER, suggesting no alterations in the neural mechanisms underlying RFD. RFD100–200 reduction suggests that impairments in the rapid force-generating capacity are located within the skeletal muscle, likely due to a reduction in muscle–tendon stiffness and/or impairments in the muscle contractile apparatus. These findings may help explain evidence of neuromuscular alterations in trail runners and following prolonged duration races wherein cumulative eccentric loading is high.

Fatigue in elite fencing: Effects of a simulated competition

“…Although the decreased maximal torque of ~17.8 Nm for the simulated competition might be considered as limited, the decreased rate of torque development was ~100 Nm s −1 (~10%). This loss in rate of torque development could be relevant, considering that recently it has been reported a loss of ~15% following an intense downhill running session using similar methods 32 . The decrease in the rate of torque development would indicate an impairment in the ability to rapidly develop muscle force along a competition day, and could be a more appropriate measure than maximal torque to detect alteration in neuromuscular function induced by fast contractions 13 …”

“…This loss in rate of torque development could be relevant, considering that recently it has been reported a loss of ~15% following an intense downhill running session using similar methods. 32 The decrease in the rate of torque development would indicate an impairment in the ability to rapidly develop muscle force along a competition day, and could be a more appropriate measure than maximal torque to detect alteration in neuromuscular function induced by fast contractions. 13 This is the first study that studied both fatigue and effort in fencing.…”

Long-Chain Omega-3 Fatty Acid Supplementation and Exercise-Induced Muscle Damage: EPA or DHA?

“…Eccentrically biased exercise, especially DR, has been shown to impair muscular strength and function (38,39). However, leg strength was not significantly decreased at 24 or 72 h in the EPA or DHA groups.…”

Downhill running increases markers of muscle damage and impairs the maximal voluntary force production as well as the late phase of the rate of voluntary force development

“…Unilateral right limb knee extensors MVIC was assessed with the participants seated with the hip and knee angles at 90° on a customized seat with a calibrated force transducer (Legcontrol, Mtraining, Ecole Valentin, France). In line with a previous investigation (Varesco et al 2022 ), the lever arm of the dynamometer was adjusted to firmly attach the leg 3 cm above the medial malleoli with two non-compliant belts and a belt strapped over the waist was used to minimize extraneous movements of the upper body. Passive resting force was subtracted from the signal so that the baseline was set at 0 N (Varesco et al 2022 ).…”

“…In line with a previous investigation (Varesco et al 2022 ), the lever arm of the dynamometer was adjusted to firmly attach the leg 3 cm above the medial malleoli with two non-compliant belts and a belt strapped over the waist was used to minimize extraneous movements of the upper body. Passive resting force was subtracted from the signal so that the baseline was set at 0 N (Varesco et al 2022 ). Force signals were collected without analogical filters at a frequency of 2 kHz by PowerLab System (16/30-ML880/P, AD Instruments, Bellavista, Australia).…”