Practical applications of biomechanical principles in resistance training: neuromuscular factors and relationships

This paper is the second in our three part series examining how a variety of biomechanical principles and concepts\ud have direct relevance to the prescription of resistance training for the general and athletic populations as well as for\ud musculoskeletal injury rehabilitation. In this paper, we considered different neuromuscular characteristics of resistance\ud exercise. We started by defining the causes of motion, discussing force and Newton’s second law of linear motion. This\ud led to discussion of impulse, and how its relationship with momentum can be used to study force-time curves recorded\ud from different ground-based resistance exercises. This enables the sports biomechanist to derive movement velocity,\ud which enables study of the relationship between force and velocity, and we concluded that as the force required to\ud cause movement increases the velocity of movement must decrease. This relationship is critical because it enables\ud strength and conditioning coaches and exercise professionals to manipulate resistance-training loads to maximise\ud training gains for sports performance. We described representative force-time curves from basic human movements\ud to provide a foundation for discussion about how different resistance-training gains can be achieved. This focused on\ud exercise technique, including use of the stretch-shortening cycle, magnitude of load, ballistic resistance exercise, and\ud elastic band and chain resistance (although elements of this will receive greater attention in our final article). Finally, we\ud defined and explained the concept of mechanical work and power output, examining the effect that load has on power\ud output by considering the load-power relationships of different common resistance exercises. We hope that exercise\ud professionals will benefit from this knowledge of applied resistance training biomechanics. Specifically, we feel that\ud the take home message of this article is that resistance exercise load and technique can be manipulated to maximise\ud resistance-training gains, and that this can be particularly useful for athletes trying to improve sporting performance