So yes, the overcoming isometric should feel powerful and forceful while also producing significant intramuscular tension on the targeted musculature. Lower or higher positions can also be employed periodically to work on specific sticking points that lifters may experience on certain portions of their lifts.
It should also be noted that as long as maximal effort and exertion are used close to, or near maximal levels, of activation will occur in the targeted musculature. With that said, what is likely to change based on the depth or ROM is the targeted muscle(s) that is emphasized.
For instance, performing the overcoming isometric closer to the bottom or 90-degree position of a chest press will likely target the chest and shoulders to a greater extent as well as the outer regions of the pectorals, whereas a higher position will likely target the triceps and inner chest more so with less emphasis on the shoulders. Similarly, an overcoming isometric near the 90-degree bottom position of a squat will likely result in a roughly equal level of quads and glute activation whereas higher positions will likely be predominately quads.
Rest Periods for PAP on Explosive Movements
Although the research is quite mixed with regards to the exact length of rest periods needed to maximize the PAP response, current practice suggests one should rest 2-10 minutes before moving to an explosive activity in order to ensure fatigue accumulation doesn’t outweigh the potentiation response. The stronger you are, the more time you’ll need to allow fatigue to dissipate.
However, waiting longer than 10-15 minutes can cause the potentiation response to gradually dwindle. Many folks will find they need experiment and go through some trial and error testing to figure out the optimal length of time they need to rest and recuperate in order to maximize the PAP response as it is likely to be quite individualized.
Frequency of Implementation
Due to the extreme strain they place on the nervous system and the amount of tension the musculoskeletal system is subjected to, overcoming isometrics should be used somewhat sparingly. As far as the maximum recommended frequency, I generally suggest no more than 3 sets per muscle group, or lift, and no more than once per week per muscle, or lift, as more than this may lead to symptoms of overtraining. However, the implementation of the eccentric isometrics in conjunction with the overcoming isometrics may help prevent overtraining since eccentric isometrics generally help with recovery due to their therapeutic effects.
Solo vs Supersets
While one of the main goals of overcoming isometrics is to elicit a post activation potentiation response in order to produce greater power output on subsequent explosive activities, they can also be performed for other reasons. In fact, the benefits of performing overcoming eccentric isometrics are so numerous that simply performing them as one of the main functional strength and hypertrophy exercises for the day is not only acceptable but beneficial for reasons discussed below.
17 Additional Benefits of Overcoming Eccentric Isometrics
More research is needed but, based on principles of muscle physiology and neurophysiology, there are 17 likely benefits of combining eccentric isometrics with overcoming isometrics. Read more about eccentric isometrics here.
1. Increase proprioceptive feedback and kinesthetic awareness produced by muscles spindles that are primarily activated under loaded stretched conditions. This helps optimize body mechanics, form, and technique. Most overcoming isometric conditions don’t provide such a benefit as in the absence of an eccentric element proprioceptive feedback is limited.
2. Increase ability to recruit high threshold motor units in light of the fact that muscle spindle activation from gamma motor neurons has been suggested to indirectly increase overall motor unit recruitment and neural drive via alpha gamma co-activation.
3. Enhance activation of the stretch reflex which likely contributes to greater force production and power as well as athletic performance.
4. Decrease onset of fatigue associated with pre-stretching the muscle prior to concentric contractions. Studies of muscle fatigue suggest that eccentric contractions and pre-stretch not only help delay the onset of fatigue they also increase force capabilities, both of which are a critical aspect of maximizing potentiation, proprioception and motor programing.
5. Maintain optimal length tension relationship of muscles as the muscles will be lengthening and shortening under tension rather than just shortening.
6. Provide a semi-adjusted strength curve similar to accommodating resistance. Overcoming eccentric isometrics produce an effect similar to that of accommodating resistance protocols such as band resistance, chains, and band assistance (reverse bands). That’s because the bottom eccentric isometric position involves somewhat lighter loads of 30-70% 1 RM while the degree of force and tension produced by the overcoming isometric against the pins (typically at mid range height) are greater than 1RM provided the individual is using maximal exertion during the overcoming isometric as they should be.
7. Allow the eccentric isometric and overcoming isometric to work synergistically. In essence, the eccentric isometric helps wake up additional motor units via pre-stretch and alpha gamma co-activation associated with muscle spindle activation. This produces a stronger and more forceful overcoming isometric with greater motor unit recruitment and force production and ultimately leads to greater potentiation. The greater potentiation then feeds right back into the eccentric isometric allowing greater co-contraction of agonists and antagonist muscles thereby enhancing the slingshot effect.
8. Enhance the power and force used to drive against the pins and move into the overcoming isometric as the eccentric isometric acts as a recoil or reloading of the muscles, much like a slingshot, as opposed to driving hard into the pins from a standstill position without pre-stretching/pre-loading the muscles before hand. In fact, the athlete should feel that the eccentric isometric hold makes the overcoming isometrics feel more locked in and more powerful not only because of the delayed fatigue associated with pre-stretching but also because of the previously mentioned reloading effect.
9. Improve muscle growth and hypertrophy. Overcoming eccentric isometrics involve all 3 mechanisms of muscle hypertrophy including mechanical tension, muscle damage, and metabolic stress. Traditional overcoming isometrics involve only 2 of these mechanisms namely mechanical tension and metabolic stress.
10. Produce greater post activation potentiation by reducing fatigue as the ability to balance activation and fatigue appears to be one of the most critical components for maximizing PAP.
11. Prevent autogenic inhibition, i.e. the neurologic inhibitory response produced by Golgi tendon organs in response to excess tension on tendons. Activation of muscle spindles has been shown to potentially offset this effect since these mechanisms are polar opposites. In other words, they cannot occur simultaneously at high levels due to the fact that activation of intrafusal fibers/muscle spindles would override the inhibition from Golgi tendons organs given muscle spindles have faster conducting axons than Golgi tendon organs.
12. Help optimize proprioception on the subsequent eccentric isometric likely contributing to an improved ability to fine-tune body positioning on that eccentric isometric by increasing muscle stiffness as proprioceptive feedback is strongly dependent on the ability to maintain high levels of intramuscular stiffness.
13. Improve ability to co-contract reciprocal muscle groups (agonist and antagonists) during the eccentric and eccentric isometric phases, a critical component of eccentric contractions, as a result of the high levels of muscular stiffness produced from the prior overcoming isometric.
14. Enhance motor control and stability on the eccentric and eccentric isometric phases. These elements have been shown to be directly linked to co-contraction of reciprocal muscle groups which, as noted above, are enhanced by the prior overcoming isometric.
15. Produce greater neural drive, force, and power output on the subsequent overcoming isometric as eccentric induced co-contraction contributes to greater reciprocal inhibition and firing of the agonists on that subsequent concentric contraction/overcoming isometric.
16. Reinforce greater levels of maximal effort and maximal intensity muscular contractions on both ends of the movement as the overcoming isometric and the eccentric isometric help feed off each other since both are intended to be maximal exertion regardless of the load. In fact many individuals have difficulty with the notion that eccentric isometrics are intended to be maximal effort in the bottom or 90 degree stretched position as the lifter should be using maximal effort to create as much co-contraction as possible by squeezing into the movement with their reciprocal muscles. The max effort overcoming isometric helps create a max effort mindset that translates to maximal exertion eccentric isometrics with very high levels of co-contraction.
17. Provide high intensity training options with maximal exertion that are very joint friendly and low impact since light to moderate loads can be effectively employed while still producing a strong training stimulus.
