Three electromyography lab activities to investigate skeletal muscle physiology in an undergraduate human physiology course

Laboratory experiences are critical components of undergraduate physiology education. However, not all basic physiologic processes are easily studied in an undergraduate human physiology lab. Experiments in muscle physiology often require isolating single-muscle fibers, experimenting on animals, or large or prohibitively expensive equipment such as isokinetic dynamometers. Furthermore, these methods often require considerable time, training, and preparation by instructors. Although simulation experiments are available, the opportunity to collect and analyze real-world data is often limited in undergraduate physiology labs. To address the need for muscle laboratory activities, we developed three lab activities that use BIOPAC hardware to investigate skeletal muscle physiology. In the first activity, students investigate the relationship between motor unit recruitment and muscle activation by comparing electromyography (EMG) traces from slow versus explosive push-ups. Students observe that higher contraction velocities are associated with increased EMG activity as a proxy measure of increased motor unit recruitment. In the second activity, students assess muscle fatigue and motor unit recruitment by performing push-ups to task failure. Results show that EMG activity increases with proximity to task failure, again reflecting greater motor unit recruitment. In the third activity, students use 3D-printed spacers in conjunction with handgrip dynamometers to examine the length-tension relationship. Students complete four maximal isometric contractions without a spacer (0 mm) and with 10-, 20-, and 30-mm spacers while collecting EMG data from the forearm flexors. By plotting maximal isometric force of each contraction against their mean integrated EMG, students produce a graph showing that maximal isometric force falls despite similar maximal voluntary effort across spacings. Collectively, these labs allow students to experience and measure fundamental aspects of skeletal muscle physiology within a 50-minute class period. Advantages of these lab activities include reduced costs, time-efficient data collection, the ability to use existing equipment, and procedures that could generalize to other physiology data collection systems. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.