The Effects of Cryotherapy on Ground-Reaction Forces Produced during a Functional Task

Objective: To determine whether a standard 20-min ice-bath (10°C) immersion of the leg alters vertical ground-reaction-force components during a 1 -legged vertical jump. Design: A 1 × 5 factorial repeated-measures model was used. Setting: The Applied Biomechanics Laboratory at The University of Mississippi. Participants: Fifteen healthy and physically active subjects (age = 22.3 ± 2.1 years, height = 177.3 ± 12.2 cm, mass = 76.3 ± 19.1 kg) participated. Intervention: Subjects performed 25 one-legged vertical jumps with their preferred extremity before (5 jumps) and after (20 jumps) a 20-min cold whirlpool to the leg. The 25 jumps were reduced into 5 sets of average trials. Main Outcome Measures: Normalized peak and average vertical ground-reaction forces, as well as vertical impulse obtained using an instrumented force platform. Results: Immediately after cryotherapy (sets 2 and 3), vertical impulse decreased (P = .01); peak vertical ground-reaction force increased (set 2) but then decreased toward baseline measures (P= .02). Average vertical ground-reaction force remained unchanged (P >.05). Conclusions: The authors advocate waiting approximately 15 min before engaging in activities that require the production of weight-bearing explosive strength or power.