Temporal patterns of knee extensor isokinetic torque strength in male and female athletes following comparison of anterior thigh and knee cooling, over a rewarming period

Abstract

Context

The effect of local cooling on muscle strength presents conflicting debates, with literature undecided as to the potential implications for injury, when returning to play following cryotherapy application.

Objective

To investigate concentric muscle strength following local cooling over the anterior thigh compared to the knee joint in males and females and the temporal pattern over a 30-minute rewarming period. Design Repeated measures cross-over.

Method

Twelve healthy participants randomly assigned to receive one location of cooling intervention, directly over either the anterior thigh or knee, returning 1 week later to receive the opposite cooling location. Muscle strength measured via an Isokinetic Dynamometer (IKD) at multiple timepoints (immediately post, 10, 20 and 30 minutes post) coincided with measurement of skin surface temperature (Tsk) using a non-invasive infrared camera (ThermoVision A40M, Flir Systems, Danderyd, Sweden).

Results

Significant main effects for time (p ≤ 0.001, É32 = 0.126), with pre ice application higher than all other time points (p ≤ 0.05) were demonstrated for both peak torque (PT) and average torque (AvT). There was also significant main effects for isokinetic testing speed, sex of the participant and position of the ice application for both PT and AvT (p ≤ 0.05). Statistically significant decreases in Tsk were reported in both gender groups across all time points compared to pre-intervention Tsk for the anterior thigh and knee (p < 0.05).

Conclusion

Reductions reported for concentric PT and AvT knee extensor strength in males and females, did not fully recover to baseline measures at 30 minutes post cryotherapy interventions. Sports medicine practitioners should consider strength deficits of the quadriceps after wetted ice applications, regardless of cooling location (joint/muscle) or gender. Keywords Isokinetic dynamometry, cryotherapy, knee, quadriceps, strength, thermal imaging.