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 30 minutes after each experimental condition. At 5 minutes, 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); 30 minutes 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 5 minutes;
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.