Jump to it: the best recipe for performance!

SPB looks at new research on the benefits of plyometrics for increased lower-limb stiffness, and how to construct an effective plyometrics program

As regular subscribers will already know, a properly constructed strength-training program produces numerous benefits for athletic performance. These include a reduced risk of injury due to increased muscle and connective tissue resilience, greater levels of strength and power, and improved muscle efficiency, which enhances endurance performance. Most studies on strength training have employed some kind of resistance training intervention using free or machine weights. However, there are other modes of strength training known to be beneficial to athletes, one of which is ‘plyometrics’.

Plyometrics matters

Plyometrics training uses the principle of a quick-fire action and reaction between two muscular actions – a shortening and a lengthening one. The former is known as a concentric muscular action and the latter an eccentric one. For example, in the drop/depth jump, which involves jumping from a raised platform onto the ground, upon which a rebound jump is immediately made, the muscles, ligaments and tendons surrounding the ankle, knee and hip joint will undergo a stretch (eccentric action), immediately followed by shortening (concentric action) and a release of energy.

The fast eccentric-concentric transition movement generated in plyometrics training is a particularly useful method of developing functional strength since it helps develop improved power generation through storage and re-utilization of elastic energy⁽¹⁾. This increased ability to store and then release elastic energy arises through increased ‘stiffness’ of the joint/muscle system.

Studies on elite East African runners with extremely high levels of running efficiency have concluded that superior levels of muscle/joint stiffness play a significant role in enhancing performance⁽²⁾. In particular, research investigating elite runners performing plyometrics-type hopping drills found that, compared to their European counterparts, Kenyan runners tended to have a superior stretch-shortening cycle (SSC) as a result of high joint stiffness – great for efficient endurance running⁽³⁾!

But it’s not just about elite athletes. The use of plyometrics training (which specifically targets multi-joint SSC) in older adults, could be particularly beneficial – especially considering that as the human body ages, the utilization of elastic energy becomes gradually impaired due to neural and structural changes in older muscles⁽⁴⁾. And in a recent study on older men who either trained using conventional resistance methods or plyometrics, this was found to be the case; the plyometrics-trained group achieved significantly greater gains in performance when tested for functional strength – ie jump height, jump power, contraction time of jumps and stair climbing performance – compared to the resistance-trained group⁽⁵⁾.

Putting together a program

Many athletes who may be tempted to integrate some plyometrics into a training program for the first time can feel confused about how best to do this, especially if they train independently without the guiding hand of a coach. If developing lower-limb stiffness is your goal (beneficial for any sport that involves any type of running activity), the exercises outlined in figure 1 below can form a good starting point. But what about the structure of a program, its frequency and its duration? What works best for those who are new to plyometrics training?

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Figure 1: Examples of commonly used plyometrics exercises to improve joint stiffness

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Newly-published research on this topic published in the Journal of Sport and Health Science makes for informative reading⁽⁶⁾. In this study, researchers carried out a systematic analysis of all previous research on this topic examining the effects of plyometrics jump training (PJT) on lower limb stiffness. The studies examined where those where healthy males and females undertook a plyometrics jump-training (PJT) program isolated from any other training type – ie not while simultaneously performing resistance training. An analysis of the data resulted in the following conclusions:

• All the subjects who performed PJT experienced increases in lower-limb stiffness (a good thing) but those who were relatively untrained experienced the greatest gains.
• Programs lasting seven weeks or more resulted in greater stiffness gains overall than programs lasting less than seven weeks.
• Gains were greater when PJT was performed twice per week or less.
• Programs that totalled less than 250 jumps per week resulted in greater gains than those totalling 250-500 jumps per week. Programs involving more than 500 jumps per week resulted in a decline in lower-limb stiffness.
• Programs with eight or more jumps per set resulted in greater stiffness gains than programs with seven or less jumps per set.

In summary then, the best programs were ones that were seven weeks in duration or longer, performed just once or twice per week with no more than 250 jumps accumulated per week, but where each set contained eight or more jumps. Overall, it seems that lower volume training performed for longer is better than performing a higher volume for shorter periods of time!

Other tips

As with all new modes of training, a gradual introduction is better than going in flat out. If you’re new to plyometrics, you should first ensure that your jumping technique is correct in order to minimize the risk of injury ( provides some very useful tips). Then slowly build up your sets and reps to allow the joints and muscles to adapt to the new loading pattern. For example, you could progress from two sets of eight reps for two exercises, and gradually increase over a period of 4-6 weeks until you are performing three sets of 10 reps for four exercises (240 jumps per week total). If you are completely new to strength and conditioning, it’s a good idea to perform 2-3 months of some basic resistance training before moving onto plyometrics, which will enable muscles tendons and ligaments a greater chance to adapt!

References

1. Med Sci Sports. 1978; 10(4):261–5
2. Eur J Appl Physiol. 2015 Apr;115(4):849-59.
3. Eur J Appl Physiol. 2013 (15)Jun;113(6):1395-1403
4. J Appl Physiol (1985). 2012; 113(10):1537–44
5. PLoS ONE 2020 Aug 25th 15(8): e0237921
6. J Sport Health Sci . 2021 May 22;S2095-2546(21)00053-3