Catching More Air
By Fabio Comana, MA, MS, NASM-CPT, CES, PES, NASM Faculty Instructor
Watching Houston Texans defensive end JJ Watts (6’5” or 1.96m; 289 lbs. or 131.4 Kg) complete a plyo box jump of 59.5 inches (1.51 m) is impressive, especially when you consider that the height of the box is approximately level with his chest. Obviously, this not only demonstrates amazing power, but also great technique in harnessing this power.
Power training is synonymous with the explosive movements of plyometric training. Plyometrics is built upon various scientific principles (stretch-shortening cycle; optimizing sarcomere length, and stretch reflexes to a lesser degree) that can help individuals tremendously boost their power output (1, 2). Although plyometric training can add a fun and challenging component to training programs, like most, it must be introduced, coached, and progressed systematically in order to avoid injuries. Although jumps in place (e.g., jumping jacks) and box jumps are relatively easy to perform (just avoid catching your shins on the boxes); it is bounding (single-leg take-off, opposite leg-landing), hops (single-leg take-off, same leg-landing), and depth jumps (e.g., dropping off elevated platforms, absorbing impact forces eccentrically, then exploding concentrically) that demand a solid foundation of joint integrity, strength, flexibility, and technique to avoid injury.
Plyometric programs are generally developed and progressed consistent with skill-level or mastery, exercise choice, but most importantly volume. Volume is determined by the number of foot contacts (e.g., each time you land = 1 foot contact), or upper-extremity contacts completed (e.g., each time you throw a ball = contact) (Table 1-1).
Regardless, training good form with inexperienced individuals or allowing adequate dynamic warm-up with more experienced individuals to reinforce good mechanics, are critical to success and avoiding injury. Using the lower extremity as an example, when designing plyometric programs, plan to train no more than two to three times per week, with only one day being devoted to high-intensity drills like bounding, hopping or depth jumps. Use lower-intensity drills (e.g., jumps-in-place, single linear jumps like one plyo box jump) and moderate intensity-drills (multi-directional jumps or multiple linear jumps like a continuous set of plyo box jumps for 10 seconds) as part of your warm-up, or as exercises more frequently throughout the week.
The coaching fundamentals used in teaching good form begin with first instructing jump-landing mechanics and progressing the program only when form mastery is exhibited. Some coaching tips to improve jump-landing mechanics include:
Stage One: Instructing individuals how to properly hip-hinge from a standing position using a dowel or light bar and maintaining good spinal orientation as the body hinges and lowers (i.e., 3 points of contact with the bar – sacrum, thoracic spine and back of the head).
- This movement, versus a more quad-dominant lowering position reduces knee and hip shearing forces, while also loading (eccentrically) the gluteus maximus to facilitate a more powerful unloading (concentric contraction) during the triple extension phase (ankle, knee, and hip).
Stage Two: Introduce more dynamic movement from standing with a hip-hinge to triple-extension (end point on toes) movements and introduce arm swings (i.e., shoulder flexion and extension). This helps cue the mid-foot strike, rolling backwards into the heels and absorbing impact forces into the soft (elastic) structures rather than the bony structures.
- Progress by gradually lowering the body further towards the ground while cuing knee alignment over the toes and under the anterior superior iliac spine (ASIS). During periods of greatest instability in jumping (i.e., the landing instant and the instant of initiating the concentric phase), monitor knee alignment as these two times represent the greatest likelihood for valgus movement (i.e., knees collapsing inward).
- When ready, begin coaching your athletes to reduce the amortization phase or transition between the lowering and rising phases in order to harness elastic energy into motion (minimizing potential energy leaks).
- Emphasize upper extremity alignment and head position (eyes-ups, head aligned with spine) using cues like nose-over-toes or chest-over-knees at the bottom of eccentric loading phase.
Stage Three: Progress to in-place single squat jumps emphasizing small vertical take-offs and good landing mechanics.
- Land softly with mid-foot, rolling backwards smoothly.
- Cue knee alignment during periods of greatest instability.
- Cue upper extremity alignment throughout this more dynamic movement.
- Visual feedback (e.g., mirrors or video) and self-evaluation are excellent tools to utilize to increase awareness of misalignments. For example, facing a mirror and freezing just before, and just after, the amortization phases allows the individual to examine their knee alignment. Likewise, from a side view, freezing at those same instants allows the individual to examine their spinal and head alignment.
Stage Four: Introduce multiple jumps using agility ladders.
- Cue individuals to perform sequences of repeated jumps through the agility ladder squares, emphasizing technique while moving forward.
- The individual squares within one ladder or using ladders orientated in different directions provide excellent spatially-defined targets for coaching sagittal, lateral, rotational and even multi-directional jumps, bounds and hops.
- However, it is important to keep in mind that the ladders do not challenge vertical explosiveness, therefore your goal should be progress out of the ladders to clearing taller obstacles or landing on boxes. Furthermore, sports and life rarely offer such clearly-defined landing targets, so move away from them when possible.
In closing, while plyometrics can be fun, take the needed time to first prepare the body physiologically. Develop your systematic plan to advance individuals towards higher-intensity drills once they demonstrate technique mastery and can adequately tolerate jump-landing forces. Before long, they might just be on their way to achieving impressive feats like what JJ Watts makes look so easy.
- Chu, D and Myers, GD. Plyometrics: Dynamic Strength and Explosive Power. Champaign, IL. Human Kinetics (2013).
- Yessis, M. Explosive Running: Using the Science of Kinesiology to Improve Your Performance (1st Edition). Columbus, OH. McGraw-Hill Companies. (2000).