The stretch-shortening cycle (SSC) in human skeletal muscle provides a powerful model to study both normal and fatigued muscle function. In vivo force measurement systems, such as the buckle transducer and optic fiber techniques, have revealed that SSC exercises, compared to pure concentric actions, enhance performance with increased force at a given shortening velocity. This enhancement is characterized by low EMG activity during the concentric phase and a significant contribution from the short-latency stretch-reflex component. The stretch reflex plays a crucial role in force generation during the transition phase in activities like hopping and running. The amplitude of the stretch reflex and subsequent force enhancement can vary with increased stretch-load and fatigue levels. Moderate SSC fatigue may result in slight potentiation, while exhaustive SSC fatigue can significantly reduce the reflex contribution. SSC fatigue is useful for studying reversible muscle damage and its interaction with muscle mechanics, joint stiffness, and muscle spindle function. The recovery process from SSC fatigue is long-lasting and follows a bimodal trend, involving a rapid decline followed by a secondary drop. Direct mechanical disturbances in sarcomere structural proteins, such as titin, may also occur during exhaustive SSC exercise. Overall, the SSC model offers a comprehensive approach to understanding neuromuscular fatigue and its effects on muscle function.The stretch-shortening cycle (SSC) in human skeletal muscle provides a powerful model to study both normal and fatigued muscle function. In vivo force measurement systems, such as the buckle transducer and optic fiber techniques, have revealed that SSC exercises, compared to pure concentric actions, enhance performance with increased force at a given shortening velocity. This enhancement is characterized by low EMG activity during the concentric phase and a significant contribution from the short-latency stretch-reflex component. The stretch reflex plays a crucial role in force generation during the transition phase in activities like hopping and running. The amplitude of the stretch reflex and subsequent force enhancement can vary with increased stretch-load and fatigue levels. Moderate SSC fatigue may result in slight potentiation, while exhaustive SSC fatigue can significantly reduce the reflex contribution. SSC fatigue is useful for studying reversible muscle damage and its interaction with muscle mechanics, joint stiffness, and muscle spindle function. The recovery process from SSC fatigue is long-lasting and follows a bimodal trend, involving a rapid decline followed by a secondary drop. Direct mechanical disturbances in sarcomere structural proteins, such as titin, may also occur during exhaustive SSC exercise. Overall, the SSC model offers a comprehensive approach to understanding neuromuscular fatigue and its effects on muscle function.