Power output and work in different muscle groups during ergometer cycling

Area of Science:

• Biomechanics
• Human Physiology
• Sports Science

Background:

• Understanding joint-specific muscular power output is crucial for optimizing cycling performance and injury prevention.
• Previous research has focused on overall power, with limited detailed analysis of individual joint contributions during ergometer cycling.

Purpose of the Study:

• To calculate the instantaneous muscular power output at the hip, knee, and ankle joints during ergometer cycling.
• To determine the energy production contributions of major muscle groups.
• To investigate eccentric muscle action and energy absorption at the ankle joint.

Main Methods:

• Six healthy subjects cycled at a constant workload (120 W) and cadence (60 rpm) on a weight-braked ergometer.
• Subjects were filmed using a cine camera, and pedal forces were recorded using a force transducer.
• A biomechanical model based on dynamic mechanics was used to calculate muscular work at the hip, knee, and ankle joints.

Main Results:

• Mean peak concentric power outputs were: hip extensors (74.4 W), hip flexors (18.0 W), knee extensors (110.1 W), knee flexors (30.0 W), and ankle plantar flexors (59.4 W).
• The ankle joint exhibited eccentric plantar flexor action, with a mean peak power absorption of 11.4 W and negative work of 3.4 J per revolution.
• Major contributions to total positive work were from knee extensors (39%) and hip extensors (27%).

Conclusions:

• Knee extensors are the primary power producers during cycling at this intensity.
• Ankle plantar flexors play a significant role in both power generation and energy absorption.
• The findings provide detailed insights into joint-level power dynamics during cycling, useful for training and biomechanical analysis.