Power is king in the sporting world, increase power and performance will normally follow. Plyometrics are one of the well-established techniques utilised to improve power production but now research is looking into idea of performing these exercises on an inclined surface to see if we can further augment these gains.
Incline Plyo’s – What Are They?
To be honest the name pretty much says it all; plyometric exercises performed on an inclined surface. Remember that the term plyometric infers that the exercise must elicit a rapid lengthening and shortening of the muscle. Variations need not be different from ‘regular’ plyometrics and you are really only limited by your imagination. Having said that, don’t overcomplicate things or progress when you’re not ready to. The key must always be keeping the ground contact time to a minimum.
Performing Incline Plyo’s
Performing drills outside on a slope or hill would allow for the greatest range of incline drills to be performed, this gives you the freedom for horizontal and/or lateral emphasised movements, but I do appreciate that it’s not always possible to work outside. Whilst the gym may not be an environment completely conducive to incline drills, that is unless it has been very poorly built, there may well be ways around it.
Note: The following are suggestions that may work in principle. Please use some common sense if you’re using equipment not for its intended purpose.
A solid and well-secured incline board, the sort you would use for calf stretches or decline squats, would allow you to perform various hopping drills in place. A robust treadmill should also work well.
Why Incline Plyo’s Should Work
There are two factors that may contribute here:
1) Favourable Length-Tension Relationship
The primary plantar flexor is the gastrocnemius. Previous research has suggested that dorsiflexion of the ankle facilitates a more optimal sarcomere length for the gastroc. and would therefore be advantageous to force production1-2. Performing plyo’s on an inclined surface means that the ankle is in a dorsiflexed position during the propulsion phase.
2) Increased Energy Return from the Tendon
Dorsiflexion causes the Achilles tendon to lengthen. This additional elongation during incline plyo’s should result in a greater energy return from the tendon3.
The Acute Response
Acutely, Kannas et al.4 reported a 10% increase in hopping height when performing the exercise on an inclined surface (15o). The researchers found that the activity of both the soleus and tibialis anterior were significantly greater during the propulsion phase. Leg stiffness was not significantly higher, perhaps surprising given the increase in muscle activity, although was 3.9% greater on average.
The Training Response
Kannas et al5 compared groups of 10 athletes (all young males but no training history given) performing plyo drills on an incline (15o) or flat surface. Athletes performed 8 sets of 10 consecutive jumps on 4 days a week and for 4 weeks. The incline group showed significant improvements in fast depth jump performance (17% from a 20cm drop, 14% from 40cm) with activity of the gastroc. during the propulsion phase also increased during these jumps. Whilst the incline group demonstrated a tendency for slight increases in squat, countermovement and slow depth jump performances, these were not significant. Fast depth jumps were classified by <50o of knee flexion, slow depth jumps by >60o of flexion.
Incline plyometrics show great promise as a potential technique for improving explosive plantar flexion. Of course, further research is necessary to determine their effectiveness in different subject populations, over a longer time course and over different exercise variations. We also do not know how the extent of the incline may or may not affect the training adaptations.
Personally, I would suggest that incline variations may warrant consideration for athletes competing in typically ‘plyometric’ sports. These exercises, however, should only be implemented at an advanced level and when an appropriate plyometric base has been achieved.
- 1. Kawakami, Y, Ichinose Y, and Fukunaga, T. Architectural and functional features of human triceps surae muscles during contraction. J. Appl. Physiol. 85(2): 398–404, 1998.
- 2. Maganaris, CN. Force-length characteristics of the in vivo human gastrocnemius muscle. Clin. Anat. 16(3): 215–223, 2003.
- 3. Lichtwark, GA, and Wilson, AM. Interactions between the humangastrocnemius muscle and the Achilles tendon during incline, level and decline locomotion. J Exp. Biol. 209(21): 4379–4388, 2006.
- 4. Kannas, TM, Kellis, E, and Amiridis, IG. Biomechanical differences between incline and plane hopping. J. Strength Cond. Res. 25(12): 3334–3341, 2011.
- 5. Kannas, TM, Kellis, E, and Amiridis, IG. Incline plyometrics-induced improvement of jumping performance. Eur. J. App. Phys. October 2011, published ahead of print.