Effects of warm-up on hamstring muscles stiffness: Cycling vs foam rolling.

Abstract

This study investigated the effects of active and/or passive warm-up tasks on the hamstring muscles stiffness through elastography and passive torque measurements. On separate occasions, fourteen males randomly completed four warm-up protocols comprising Control, Cycling, Foam rolling, or Cycling plus Foam rolling (Mixed). The stiffness of the hamstring muscles was assessed through shear wave elastography, along with the passive torque-angle relationship and maximal range of motion (ROM) before, 5, and 30minutes after each experimental condition. At 5minutes, Cycling and Mixed decreased shear modulus (-10.3%±5.9% and -7.7%±8.4%, respectively; P≤.0003, effect size [ES]≥0.24) and passive torque (-7.17%±8.6% and -6.2%±7.5%, respectively; P≤.051, ES≥0.28), and increased ROM (+2.9%±2.9% and +3.2%±3.5%, respectively; P≤.001, ES≥0.30); 30minutes following Mixed, shear modulus (P=.001, ES=0.21) and passive torque (P≤.068, ES≥0.2) were still slightly decreased, while ROM increased (P=.046, ES=0.24). Foam rolling induced "small" immediate short-term decreases in shear modulus (-5.4%±5.7% at 5minutes; P=.05, ES=0.21), without meaningful changes in passive torque or ROM at any time point (P≥.12, ES≤0.23). These results suggest that the combined warm-up elicited no acute superior effects on muscle stiffness compared with cycling, providing evidence for the key role of active warm-up to reduce muscle stiffness. The time between warm-up and competition should be considered when optimizing the effects on muscle stiffness.