by Antonio Robustelli
p.s. This article has been originally published on the magazine Athletics Weekly (www.athleticsweekly.com) on November 2014
Most training programmes focus on teaching the concentric portion of the jumping movement and fail to work on the eccentric where the majority of injuries usually occur.
Jump training was introduced by Professor Verkhoshansky at the end of the 1950s – the exercise of the jump executed by dropping from a height with vertical rebound has been a staple for his track and field jumpers and sprinters.
The purpose of this type of training was the increase in explosive strength.
Later in the 1960s jump training was introduced in the United States, thanks to the work of Dr Michael Yessis, while Fred Wilt, a long-distance runner and member of the US Olympic team in 1948 and 1952, coined the term “plyometrics”.
The word plyometric is apparently derived from the Greek word plethyein, which means to increase, and isometric.
In Modern Athlete And Coach (1978), Wilt wrote: “My present interpretation of the term is that it means the exercises or training drills used in producing an overload of isometric-type muscle action, which invokes the stretch reflex in muscles. I am not particularly happy with this interpretation, and it may alter when a precise definition evolves.”
As earlier noted, it is necessary to focus on proper landing technique and jumping mechanics for two main purposes: injury prevention and power output. The most recurrent injuries related to poor landing technique in jump training are ankle sprains, low back pain and even anterior cruciate ligament (ACL) tear as shown from many researches.
Neuromuscular instability paired with poor landing mechanics can represent a recipe for a high risk of non-impact knee injuries.
It is almost impossible to talk about landing technique without taking into account proper jumping mechanics, as a proper landing is a direct consequence of optimal jumping mechanics.
Hip motion is the main factor involved when jumping and landing in an efficient manner – poor strength and development of the posterior chain muscles (glutes, hamstrings, gastrocnemius, soleus, erector spinae) due to improper training programming can lead to what is called “quad-dominant” jumping.
A quad-dominant jump is the one in which the athlete shifts the weight forward through the use of the quad muscles, thus decreasing the activation of the glutes and hamstrings and putting more stress on the anterior knee structure.
A correct hip joint mechanics in jumping is one in which the athlete uses a “glute-dominant” position to reach a full extension of the hip, knee and ankle joints. The “hip-hinge” motion pattern, through the backward movement of the glutes and the anterior pelvic tilt position, allows us to pre-tension the posterior chain muscles and to achieve a full hip extension. The reason is that using this glute-dominant position we can maximise power-production and minimise injury risks (putting the load off the anterior cruciate ligament).
However, landing technique can differ depending on the goal of the jump. “Drop jumps should be executed with a hard landing, keeping the leg muscles stiff in an attempt to minimise the leg’s flexion during landing. This is a fundamental condition for the elastic energy recoil. On the contrary, in a depth jump the athlete should not land with rigid, extended legs. The landing should be resilient and elastic, with the optimal depth of knee flexion at the end of the amortisation phase” says Dr Natalia Verkhoshansky (Depth Jump vs Drop Jump, 2013).
This is because different jumping goals lead to different landing technique as in drop jumps.
Verkhoshansky adds: “The goal is to obtain the maximal height of rebound with minimal ground contact time, whereas in depth jumps the goal is to obtain the highest height of vertical rebound using the overhead goal.”
As stated by Devita and Skelly (1992), soft and stiff landings had relatively large and small amounts of knee flexion, respectively, during the floor contact phase.
The action of landing from a vertical fall applied forces and movements to the lower extremities that accelerated hip and knee flexion and ankle dorsiflexion, thus causing the extremities to collapse. The goal of a proper landing mechanics was to resist this collapse by applying counter-extensor movements at these joints in such a way that the body’s negative velocity was reduced to zero without injury.
These extensor movements primarily worked eccentrically to absorb kinetic energy from the skeletal system and stop the person’s fall.
As we need to absorb forces with muscles and not joints, proper muscle activation is fundamental both in soft and stiff landing. This is because we require an optimal co-contraction to ensure optimal stabilisation of the ankle, knee and hip joints: dynamic neuromuscular stability has a protective effect for an athlete and poor muscle activation can lead to improper dynamic stability, thus putting athletes to a higher risk of (potential) injury.
Antonio Robustelli is the mastermind behind Omniathlete Performance Science. He is a professional high performance consultant and elite s&c coach from Italy: his area of expertise includes injury prevention, sports technology, strength training programming, speed development, recovery monitoring and return to play assessment. He works all over the world since 16 years with semi-professionals, professionals and Olympic athletes as well as professional teams in various disciplines. Regularly invited as a Keynote Speaker to hold lectures during international conferences in Sports Science and Strength & Conditioning, he is also an Editorial Advisory Board member of the Lower Extremity Review, the most authoritative magazine for lower extremity biomechanics, sports medicine and rehabilitation. Currently he is consultant for Federations, Governing Bodies, Olympians and for First Division football and basketball teams in Europe, Asia and USA.