Normative Muscle Activation Patterns During One and Five Countermovement Jumps

Area of Science:

• Biomechanics
• Exercise Physiology
• Sports Science

Background:

• Understanding muscle activation patterns during dynamic movements like the Countermovement Jump (CMJ) is crucial for performance analysis and injury prevention.
• Normative data for muscle activation in key lower limb muscles, such as the vastus lateralis (VL), vastus medialis (VM), and biceps femoris (BF), are essential for interpreting individual performance and identifying potential imbalances.

Purpose of the Study:

• To determine normative values for muscle activation in the VL, VM, and BF, and the hamstrings/quadriceps (H:Q) ratio during the CMJ.
• To compare muscle activation between a single CMJ and a series of 5 consecutive CMJs (5 CMJ).
• To analyze differences in muscle activation between the take-off and landing phases within these jumps.

Main Methods:

• A cross-sectional descriptive study involving 31 healthy participants (20 female, 11 male).
• Surface electromyography (sEMG) was utilized to measure muscle activation.
• Measurements were taken during single CMJ and 5 CMJ trials, focusing on the take-off and landing phases.

Main Results:

• Normative muscle activation values were established for VL, VM, and BF during both CMJ and 5 CMJ (excluding BF during 5 CMJ landing).
• Muscle activation in the VM and VL was significantly greater during the take-off phase compared to the landing phase.
• The BF exhibited similar activation levels in both take-off and landing phases.
• The 5 CMJ protocol did not result in greater muscular fatigue compared to the single CMJ.

Conclusions:

• The study provides valuable normative electromyography data for the VL, VM, and BF during CMJ variations.
• Findings suggest distinct activation strategies for quadriceps and hamstring muscles across jump phases.
• Repeated CMJ efforts do not appear to induce significantly higher muscle fatigue than a single jump within this cohort.