Lower Limb Force Asymmetries During Landing and Jumping Exercises: A Pilot Study

Area of Science:

• Biomechanics
• Sports Science
• Human Movement Analysis

Background:

• Bilateral jumping exercises can reveal significant lower limb force production asymmetries.
• Previous research suggests asymmetries may occur during both the take-off and landing phases of jumps.
• A direct comparison of asymmetry magnitude between landing and take-off phases in bilateral jumps has been lacking.

Purpose of the Study:

• To compare the magnitude of lower body asymmetry between the landing (L) and take-off (TO) phases of bilateral jumping movements.
• To determine if significant differences exist in asymmetry levels between the L and TO phases.
• To investigate potential phase-specific differences in jump asymmetry.

Main Methods:

• Quantified lower body asymmetry using vertical ground reaction force (vGRF) measurements from each leg.
• Measured vGRF during vertical jump (VJ) and drop jump (DJ) exercises.
• Analyzed data from eleven recreationally trained individuals using two force plates and a two-way repeated measures ANOVA.

Main Results:

• A statistically significant difference in asymmetry was observed between the landing and take-off phases (p < .05).
• The study found greater asymmetry in the distribution of vGRF during the landing phase compared to the take-off phase.
• No significant interaction was found between phase and exercise type (VJ vs. DJ) for asymmetry.

Conclusions:

• Lower body asymmetry is not uniform across all phases of bilateral jumping.
• The landing phase of bilateral jumps demonstrates a higher degree of asymmetry in vertical ground reaction force distribution than the take-off phase.
• These findings have implications for understanding injury risk and performance optimization in jumping athletes.