Stability of Hand Grip Strength Across a Competitive Season in Elite Male and Female Ice Hockey Players

This is a prospective longitudinal observational cohort study designed to evaluate within-season variability and measurement stability of maximal isometric hand grip strength in elite ice hockey players.

Hand grip strength is widely used as a surrogate marker of upper-limb strength and general neuromuscular capacity. Although its reliability has been well described in clinical and general athletic populations when measured using standardized protocols, limited evidence exists regarding its temporal stability in elite collision sport athletes over an entire competitive season. In particular, it remains unclear whether grip strength behaves as a stable individual characteristic or whether it is influenced by seasonal training load, match congestion, fatigue, or adaptation effects.

The study will include elite male and female ice hockey players recruited from Swedish top-level teams. Participants will undergo repeated standardized grip strength assessments at four predefined timepoints across one competitive season: pre-season baseline, early mid-season, late mid-season, and pre-playoff/end-of-season phase. All measurements will be performed using a calibrated hand dynamometer following a standardized protocol based on established clinical measurement guidelines, including consistent body positioning, handle adjustment, and repeated maximal trials for both dominant and non-dominant hands. Mean values from repeated trials will be used for analysis.

To reduce measurement variability, all testing will be conducted by trained assessors using harmonized instructions across participating teams. Where possible, testing sessions will be scheduled to minimize acute fatigue effects by ensuring a standardized recovery period following matches or high-intensity training sessions.

The primary analytical focus is within-subject variability of grip strength across the season, quantified using measures of dispersion and reliability, including coefficient of variation (CV%), within-subject standard deviation, and intraclass correlation coefficients (ICC). Additional analyses will estimate measurement error (standard error of measurement) and minimal detectable change (MDC95) to determine the smallest meaningful change in grip strength that exceeds expected measurement noise.

Longitudinal changes in grip strength across the season will be assessed using mixed-effects statistical models to account for repeated measures within individuals and potential group-level effects such as sex and playing level.

The study does not involve any interventions, treatment allocation, or experimental manipulation. All assessments are non-invasive and conducted within routine team environments. The findings are intended to inform interpretation of grip strength in athletic monitoring, rehabilitation contexts, and performance evaluation, specifically whether single timepoint measurements can be reliably used for comparison against normative data or whether seasonality must be considered in clinical and performance decision-making.