Force-velocity profiling of sprinting athletes: single-run vs. multiple-run methods

Area of Science:

• Sports Science
• Biomechanics
• Athletic Performance Analysis

Background:

• Force-velocity (Fv) profiling is crucial for assessing sprint performance in athletes.
• Accurate Fv profiling aids in understanding training adaptations and optimizing athlete development.
• Existing methods for Fv profiling may yield different results, necessitating a comparison of their agreement.

Purpose of the Study:

• To evaluate the agreement between single-run and multiple-run methods for force-velocity (Fv) profiling in sprinting athletes.
• To assess how sprint training influences the agreement between these two Fv profiling methods.
• To determine if the methods can be used interchangeably for evaluating absolute Fv characteristics and training-induced changes.

Main Methods:

• Seventeen female handball players underwent 30m sprints under un-resisted and resisted conditions (50, 80, 110 N) before and after an 8-week training intervention.
• Theoretical maximal velocity (v0), horizontal force (F0), maximal power (Pmax), and the Fv slope (SFv) were calculated using two methods: a single-run inverse dynamics approach and a multiple-run graphical method.
• Agreement was assessed by comparing absolute values and changes over time, using correlation coefficients and effect sizes.

Main Results:

• While trivial differences were found for v0 (0.7%), substantial differences were observed for F0 (16.4%), Pmax (15.6%), and SFv (17.6%) between the methods.
• Poor agreement was found for F0 (r=0.26 pre-training, r=0.16 post-training).
• No substantial correlation was observed between the training-induced changes in SFv calculated by the single-run and multiple-run methods (r=0.03).

Conclusions:

• The single-run and multiple-run methods for Fv profiling demonstrate poor agreement, indicating they measure distinct sprint characteristics.
• These methods cannot be used interchangeably for assessing Fv relationships or training adaptations in athletes.
• Both methods may hold value, but their distinct outputs require careful consideration in practical applications and research.