Muscle Stretch Shortening in Upper Extremity Explosiveness

After talking briefly about muscle stretch shortening in class, I thought this was an interesting topic and looked into some literature to better understand what is going on. I found a study that focused on upper-body explosive movements, and how load and stretch shortening cycles (SSC) affect the kinematics, kinetics, and muscle activation that occur. This was an interesting study because they looked at maximal effort bench throws, where much of the previous research focused only on lower-extremity exercises. Each subject performed an SSC throw and concentric only throws, comparing displacement, velocity, acceleration, force, power output and EMG from the pectoralis major, anterior deltoid, and triceps brachii. SSCs are usually performed before explosive movements (e.g. throwing, jumping) which lengthen the muscle preparing to contract to ensure maximal velocity is reached during the movement. When the muscle lengthens, elastic energy is stored which can then be released during the movement, however, if the time between lengthening and contracting is too long, the energy dissipates, leading to a slower contraction with less power.

As expected, the average velocity was lower for the concentric only throws when compared to the SSC throws, however, there was no difference in throw height between the two groups. Average and peak force and power output were both higher for the SSC through compared to the concentric only throw. The findings from this study agree with findings from previous studies focusing on vertical jump, showing that similar muscle kinetics are at play. Muscle kinetics are an extremely interesting area of study, and even though we only briefly discussed muscle length-tension, force-velocity, and power relationships in class, this is a huge field of study. Some groups choose to look at specific muscle groups, while others look at more complex movements that require multiple groups of muscles to be activated. This area of research has led to improvements in stretching suggestions for athletes; stretching before performing explosive movements is not actually as beneficial as we once thought. Stretching the muscle allows for elastic energy dissipation, instead of storing the energy for immediate release. However, stretching is still extremely beneficial after workouts, helping to prevent muscle soreness and excess inflammation. Additionally, there are some chronic adaptations to stretching including increasing flexibility for a wider range of motion during typical daily activities as well as athletic endeavors.

References:

  1. Newton, R. U., Murphy, A. J., Humphries, B. J., Wilson, G. J., Kraemer, W. J., & Häkkinen, K. (1997). Influence of load and stretch shortening cycle on the kinematics, kinetics and muscle activation that occurs during explosive upper-body movements. European Journal of Applied Physiology and Occupational Physiology, 75(4), 333–342. https://doi.org/10.1007/s004210050169
  2. Bosco, Carmelo, and Paavo V. Komi. (1979) Mechanical characteristics and fiber composition of human leg extensor muscles. European journal of applied physiology and occupational physiology4 (1979): 275-284.
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8 thoughts on “Muscle Stretch Shortening in Upper Extremity Explosiveness

  1. Do you think the results would be the same if an equivalent exercise was done with legs? I like this study a lot since it explains what we learned in class as a real world experimentIn addition to proving again that stretching before exercise may not be as beneficial as assumed.

    • Thanks for your response! Yes, I think the same results would occur for a study done with exercises in the legs. Before this study, most of the stretch shortening studies were actually done using exercises that primarily focus on legs (like vertical jump), so this was an interesting study that connected previous knowledge about lower extremity response to upper extremity response.

      • Maybe the differences between the measurements would be greater since the leg muscles are larger/more powerful? I really like how it connects the two it makes them easier to understand in comparison

  2. I enjoyed this post because I can really see its application in my life. Growing up I was taught to statically stretch before sports and then as I got to high school we switched more to dynamic warm ups. We also did multiple types of jump testing in volleyball including jumping from standing or being allowed to take our approach before jumping, with the second almost always leading to a higher jump. It’s interesting to see the scientific process at work and how studies like this can actually influence everyday life.

    • I agree! Since learning more about stretching and muscle dynamics, I’ve been able to apply what I’ve learned to my my own workouts. It’s always nice when coursework is directly translatable to everyday life.

  3. Would stretching be more beneficial before longer endurance exercises or would the same principles apply where it is actually more detrimental to stretch before these events?

    • I was always taught to stretch after a warm up before long endurance exercises, like a long run. In this case, I think the same principles apply, and its probably more beneficial to stretch after the exercise is complete, but I still like to stretch a few minutes into my exercise if I’m feeling especially tight.

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