You've Got Nerve with Dr. David Behm
Fitness for Consumption ep. 8
Legendary neuromuscular physiologist, Dr. David Behm, headlines this exploration of neural adaptation. The term is ensconced in the fitness vernacular, but what, exactly, does it mean? Get ready for some true pearls of wisdom, as the team dives into motor control and specificity. They discuss Dr. Behm’s landmark research paper on intention, and wrap up with some suggestions on how trainers and strength coaches can best serve their clients. Prepare for enlightenment!
In this episode Dr. J and GG are thrilled to welcome highly respected, veteran research scientist, Dr. David Behm. If you consider yourself an avid exerciser, on any level, then you’ve been influenced by some of the research conducted by Dr. Behm, whether you know it or not.
Dr. Behm, aka Dave, is a former Canadian professional athlete (albeit a VERY short career), a neuromuscular physiologist and professor at Memorial University in Newfoundland, Canada. His research interests have spanned a wide range of topics, including, neuromotor control, resistance training, instability training, and stretching.
The episode begins with an exploration of “neural adaptation.” It’s a term that gets tossed around quite frequently, but what does it really mean? From there, Dave discusses his theories on the quantity and quality of applied forces. Diving deeper, he explains how muscle force output is graded and refined by our motor unit recruitment strategies.
Next, the guys tuck into one of Dave’s most influential studies; intended vs actual velocity, and their effects upon velocity-specific strength gains. This is a rare opportunity to hear the author of a LANDMARK study discuss his work from his own unique perspective! You definitely want to hear this!
GG then poses a question to both PJ and Dave regarding a researcher’s role in guarding and defending research outcomes, once published. You may be surprised by their responses. Finally, the gentlemen discuss some contrasting views on the role of a strength and conditioning coach in promoting skill acquisition. Is it the job of the coach to enhance the actual skill? Does mimicking a skill in the gym ultimately translate to performing that skill outside of the gym? Or is there a more critical consideration? Listen as Dr. J explains his perspective based on some of the research in the field. The episode ends with some practical suggestions on approaching the skill vs strength coaching responsibilities.
In this episode, you’ll hear about:
- The concept of neural adaptation
- Motor unit recruitment
- Intention and specificity
- Practical approaches to training
Glossary
Action potential - The wavelike conduction of a neural impulse along a motor neuron, after continued stimulation of the cell reaches its firing threshold.
Agonist - The prime mover of an action, typically identified as a muscle, but may instead be an externally applied force, or gravity.
Antagonist - The opposition to the agonist. This may be a muscle, creating tension in the opposite direction of the agonist, an external force, or gravity.
EMG - Electromyography. A process of measuring muscle activity through the use of sensors placed on the skin (surface) or in the muscle (indwelling).
Henneman’s size principle - the principle which states that motor units are recruited sequentially, from small diameter, low tension, slow twitch, to large diameter, high tension, fast twitch.
Inertia - Resistance to change. Newton’s first law of motion states that an object will remain at rest or in uniform motion unless acted upon by an unbalanced force.
Isometric contraction - Tension is generated at a constant muscle length.
Isokinetic contraction - Tension is generated while at a constant velocity.
Neural adaptation - Adaptive changes in the nervous system after exposure to a specific stimulus, allowing for improved muscular activation for the purpose of refining voluntary coordinated movement
Rate of tension development - The rate at which tension is generated in muscles. Higher rates of tension development are associated with enhanced performance.
Recruitment - A term expressing the activation of motor units.
Spatial recruitment - A process whereby multiple motor units are recruited in order to develop graded tension.
Temporal recruitment - A process whereby individual motor units are activated repeatedly, at varying frequencies, in order to develop graded tension.
Triphasic EMG - A pattern of recorded EMG activity in which agonist activity is followed by antagonist activity, and then finally, a repeated agonist burst of activity in order to stabilize a joint or modify motion.
References
Behm, D.G. and Sale, D.G. (1993). Velocity specificity of resistance training. Sports Medicine. 15(6): 374-388.
Schwendel, P. and Thorland, W. (1992). Effect of traditional vs power resistance training on improvement of baseball batting velocity. Medicine and Science in Sports and Exercise. 24(5, Supp) S137.
Szymanski, D.J. et al. (2007). Effect of torso rotational strength on angular hip, angular shoulder, and linear bat velocities of high school baseball players. The Journal of Strength and Conditioning Research. 21(4): 1117-1125.
