Guest Post from Sportland S&C Coach Marc Stevenson

For all athletes wanting to better their sporting performance and turn themselves from a ‘good athlete’ into a ‘great athlete’ they need to enhance their general movement qualities such as the ability to accelerate faster and the ability to change direction quicker. To do this, everybody knows that resistance training and particular exercise modalities can be a massive influence in this. So a commonly used method to measure the improvement of such qualities is by recording jump testing scores. This has been shown by research that there is a correlation with those athletes with higher jump scores will also possess greater abilities to produce faster speed times, quicker acceleration and change of direction.
Now, let’s bring you into my situation of late. A rugby athlete that I’m currently training has improved his standing broad jump by 20cm from his pre (220cm) to his post (240cm) testing score after his first training block. This result showed an approximate 9% increase in distance covered with only 4 weeks’ worth of a training stimulus. What is remarkable about the result is that there was no jump training of any nature prescribed during the intervention which only enhances the speculation that the particular strength programme stimulus promoted this adaptation. However, it must be highlighted that body mass consistently stayed the same throughout the intervention.
Screen Shot 2015-12-11 at 18.54.42So the question I ask myself was how can this jump result be possible with this type of goal in mind?
The overall programme focused on the standard ‘hypertrophic’ rep range (8-12 reps per set) with 8 reps being consistently performed across the major compound lifts with only load being manipulated each week. Upper and lower body were trained in this fashion with the emphasis targeting the posterior chain (hamstrings, glutes & back). With body mass not increasing throughout the 4 weeks, logically this suggests that neurological factors were the main contributors to the dramatic increase in jump performance over the short space of time.
So what could be the main variables in the programming (exercises in particular) that could’ve caused this adaptation?
There are 2 major exercises in the programme that I believed played a big role and they are the barbell hip thrusts (posterior chain strength exercise) and Eccentric high box squats (5 seconds control on the downward phase of the box squat). I will discuss why I believed they were significant in a short while.
To begin with first, different types of jumps involve the athlete to produce either vertical or horizontal force to various degrees. In terms of the broad jump, the focus is more on horizontal force production as the athlete is trying to displace his centre of mass forwards (not directly upwards). This is where posterior chain strength is crucial for broad jumping as the hips are the major joint that gets loaded during the downward phase of the movement. This ultimately means that the glutes and hamstrings get stretched causing an eccentric contraction before a rapid shortening (concentric) contraction which takes place to cause the hips to extend on take-off.
Before continuing to discuss the two exercises, another important bit of information to consider is the background history of the athlete which highlights that he has a low training age and lacks resistance training experience. In this case, the hip thrust exercise played a big role by increasing jump distance because the exercise simply improved the athlete’s ability to create a faster neural signal that promoted a stronger, excitable contraction of the glutes. This has subsequently transferred over to his performance by generating greater horizontal forces produced on take-off through the extension of the hip joint.
Nevertheless, the second exercise I’ve previously mentioned was the 5 second eccentric box squats. I believe this contributed to the increase in jump distance because the exercise strengthens the downward phase of a jump. The idea of eccentric box squats is to really emphasise slowing down the eccentric movement (downward phase) which increases the force production of the muscle contraction whilst being stretched. This ultimately allows the muscle to handle more force (increase the tension when lengthening) which subsequently increases the muscles force production when shortening (concentric activity). This coincides with the decision of box squatting. My justification is that box squatting breaks up the eccentric-concentric chain which creates reciprocal inhibition. This simply means that this method is trying to teach the peripheral nervous system to switch off adjacent muscle group to effectively fully fire the appropriate muscle group of that given joint. In the context of this example which surrounds the hip joint, when standing up from squatting to a box, the ideal sequence of hip extension is to have the hip flexors relaxed to facilitate a forcefully contraction of the glutes. Meaning if the hip flexors are over active whilst the hip is extending, this reduces force production from the glutes, which will cause energy leaks in the hip joint and result in other muscles needing to compensate and act as the prime movers to extend the hip.
Overall, giving the athlete’s low training background, performing three sets of eight reps on both exercises was a sufficient enough stimulus to cause a positive neurological change. This allowed the motor skill pattern to be developed through many repetitions of that specific movement and allowed the nervous system to synchronize motor units and increase the firing rates within the motor complex.

Bio:

Bio
Screen Shot 2015-12-13 at 13.20.16I begin my S&C career by completing a strength and conditioning foundation degree through Plymouth University. There I picked up experience by working with Tennis and Rugby athletes before moving up to Twickenham, St. Mary’s to complete my full S&C Bachelors Honours. Currently I’m an assistant S&C coach at Sutton Tennis Academy and Amersham & Chiltern Rugby Club whilst also being employed as a S&C coach by Sportland & Fitness working on various different projects.

Follow Marc on twitter @Marco_Stevenson

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