Acute effects of cryotherapy duration on upper extremity muscle strength, flexibility, endurance, and balance: a randomized trial
摘要
To compare the acute effects of different cryotherapy (CT) durations on shoulder muscle strength, flexibility, endurance, and upper extremity dynamic balance in healthy individuals.
MethodsSeventy-five healthy participants (51 females, 24 males; mean age 20.47 ± 1.32 years) were included in this prospective, single-blind, randomized trial. The participants were randomized into three groups (n = 25 per group) based on the duration of CT application: 10, 15, and 20 min. The primary outcome was muscle strength (hand-held dynamometer); secondary outcomes included upper body flexibility (Back Scratch Test), muscular endurance (Modified Push-up Test), and dynamic balance (Upper Quarter Y-Balance Test). All outcomes were assessed immediately pre- and post-CT application.
ResultsNo significant between-group differences were observed for any outcome following cryotherapy protocols, and effect sizes were generally small (partial η²=0.002–0.075, p > 0.05), indicating that the primary hypothesis was not supported. Exploratory within-group analyses demonstrated small reductions in external rotation strength after the 15-minute application (Δ=-1.02 kgF, d = 0.30) and in abduction strength after the 20-minute application (Δ=-0.99 kgF, d = 0.22), whereas no significant strength reductions were observed following the 10-minute application. Increases in endurance were observed across all groups (d = 0.28–0.43), and improvements in external rotation flexibility were noted following the 10- and 20-minute applications (d = 0.19–0.23). Dynamic balance was largely maintained, although an improvement in medial reach distance was observed in the 10-minute group (Δ = 3.45%, d = 0.46).
ConclusionsThe 10-, 15-, and 20-minute cryotherapy protocols were associated with comparable acute responses in upper-extremity performance, with no between-group differences observed. Exploratory within-group analyses indicated favorable flexibility and endurance responses across durations, while small reductions in specific strength measures occurred only after the longer applications. Therefore, these findings remain exploratory, and no protocol demonstrated clear superiority.
Trial registrationClinicalTrials.gov NCT05355584 (20/04/2022).