Velocity Loss During Resistance Training

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Sometimes I love to do some challenging training exercises that to the worlds eyes, I know, look crazy. Last summer I spent 92 minutes of my life on the Air Dyne, also called “Hell Dyne”, with the aim to burn 1000 calories as fast as possible. One month ago I did the “30 minutes squat challenge”, in which I tried to perform the highest number of squats with a load of 60kg in 30 minutes. You can see the results of this crazy idea below thanks to Beast Sensor, that assisted me and counted every single rep.

squat challenge

 

My first aim was testing my mental strength and the reaction of my body in quite an extreme new challenge to see what would happen. The energetic and muscular demand requested by these exercises are completely different: one is an aerobic exercise and the other is an anaerobic exercise; one involves the upper and the lower body, squat only involves the lower (even it isn’t completely true, because my arms and my back were screaming too); the duration of the effort has been different (92 minutes against 30). However, what happened in both of these cases was that after a certain period of time, fatigue unleashed its effects: my muscles started to shake and a little voice in my mind was whispering to me “Why are you doing this?”, “You can stop whenever you want” and so on. The perception of the effort was huge and even though I was doing my best, the level of my performances kept on decreasing. I was enable to sustain the same power output on the Air Dyne and I couldn’t do more than 5 squats in a row. Fatigue was compromising the capacity of my muscles to generate the same amount of force.

Even science is not still able to define what causes fatigue with certainty due to the different measurement systems used in the researches to quantify them, the effects are well known to every athlete and coach. They can be manifested in: a motor deficit, a decline in mental functions, a decrease in force capacity and so on. They are different under various conditions, because they are task-specific. 1)“Muscle Fatigue: what, why and how it influences muscle function” R.M. Enoka, J. Duchateau. The Journal of Physiology

In Resistance Training, the effects of fatigue have been shown to limit not only the capacity of the muscles to generate force but also the maximum velocity of shortening, together with a slowing of the relaxation, resulting in a decline in force, velocity and power. Research has shown that there is a high correlation between Velocity and Power Loss and the demand of effort, thus by monitoring repetition velocity, it is possible to estimate the metabolic stress and neuromuscular fatigue induced by the lifts. 2)“Velocity Loss, an indicator of neuromuscular fatigue during resistance training” Sanchez-Medina, Gonzalez-Badillo. Medicine and Science in Sport and Exercise.

Gonzalez-Badillo and Sanchez-Medina measured the correlation between velocity loss (Mean Propulsive Velocity) in Bench Press (BP), Squat (SQ) and Counter-movement Jump (CMJ) height with Lactate Blood and Ammonia levels.3)“Velocity Loss, an indicator of neuromuscular fatigue during resistance training” Sanchez-Medina, Gonzalez-Badillo. Medicine and Science in Sport and Exercise.

Here is what they found:

  1. Velocity losses were higher as the number of repetitions performed approach the maximum number predicted for each exercise;
  2. Velocity Losses in the BP were higher than in the SQ;
  3. Peak Post-Exercise Lactate concentration linearly increase as the number of repetitions performed approach the maximum predicted number of rep in BP, SQ and CMJ;
  4. Lactate Levels were always higher after SQ compared with BP;
  5. There is a a nearly perfect correlation between Mean Propulsive Velocity (MPV) loss and post-exercise Peak Lactate;
  6. Peak post-exercise Ammonia concentration increased only when the number of rep performed were over the half of the maximum predicted number (over 3 sets of about 30% for SQ and about 35% for BP);

The greater MPV losses in BP are attributed to the different velocity in which 1RM is reached, that in the BP is about 0,16 m/s and in the SQ is about 0,35 m/s. This difference could be related to the greater movement control and the smaller muscular groups involved, in addiction with different sticking points and the effect of the rebound during the SQ.

What emerges in this research is that there is a high correlation between intensity of the load, number of repetitions performed in each set, metabolic fatigue indicators (Ammonia and Lactate) and Velocity (MPV).  

This means that by using velocity in order to prescribe training loads, instead of a relative percentage, or by both, a coach can control not only the effort, but also a very precise level of neuromuscular stress.

References   [ + ]

1. “Muscle Fatigue: what, why and how it influences muscle function” R.M. Enoka, J. Duchateau. The Journal of Physiology
2, 3. “Velocity Loss, an indicator of neuromuscular fatigue during resistance training” Sanchez-Medina, Gonzalez-Badillo. Medicine and Science in Sport and Exercise.
Martina Marson

by Martina Marson

From kick boxing to free style wrestling, through functional and strength training. Beast Sensor addicted. Training is my job, my passion and my life.