Some of the latest and greatest programs and philosophies in the sport performance world, particularly those revolving around concepts of neurological adaptation, have included the utilization of various forms of isometrics.
Isometrics have been much of a pendulum concept, swinging in and out of the performance world, always with anecdotes of good results from their use. My own first experience with them was Larry Van Such’s book, which featured basic banded holds in sprint positions. From there, we have the more integrated and progressed models of Jay Schroeder, Inno-sport, Triphasic Training, and more.
The best iteration I’ve heard recently through the utilization of isometrics is Alex Natera. Alex has been on fire on a series of podcasts, and is doing amazing work at Aspire Academy getting already high-level athletes faster using a progression of isometric based work. The following Q&A will span various methods and means for speed building isometrics, and reads more like an article. I trust you’ll enjoy this great work from Alex Natera. In the work I’ve done in the last few years compiling a significant body of work on speed and strength training, this work by Alex really puts a lot of puzzle pieces together, and the results show it.
As you read through, Alex demonstrates the isometric training terms you may not be familiar with in question one via visuals and graphs in question 2.
How do you program or incorporate maximal isometric holds for your sprinters?
Alex Natera: Well firstly, from a classification standpoint, Holds (aka “yielding” isometrics) are the first progression of a 4 stage isometric continuum that I program. From an intensity perspective (lower to higher intensity) I prescribe:
- Isometric Holds (Iso-Hold)
- Isometric Pushes (Iso-Push) (aka isometric maxes or “overcoming” isometrics)
And then finally
- Quasi isometrics- Isometric Switches (Iso-Switches) and
- Isometric Catches (Iso-Catches)
My reference point for intensity comes from force plate measurements. For each of the targeted joints (ankle, knee and hip) I derive a measure of absolute isometric force in the key positions that I perform the exercises in (if you like a Maximal Voluntary Contraction [MVC]).
I then get an understanding of the athlete’s maximal output and I then extrapolate this output back to an external load while factoring in the body mass that is being supported by the working limb (see Figure 7. Iso-Push for the output ranges normally found). I always work off of one limb, I figure if I’m going to get specific with muscle action I might as well get specific with the base of support. With the Iso-Holds I work from the unloaded system mass up to a total system mass of up to 75-80% of the total output (i.e. system mass + external load = 75-80% of MVC).
In terms of programming for sprinters I incorporate a lot of eccentric work on these specific joints and surrounding musculature during early GPP. I firstly work off of controlled eccentric exercises, focused primarily on TUT (approx. 6 secs- eg. 80-110% 1RM) and then as the athlete is able to control the heavier loads I move into an “unsuccessful braking” strategy (i.e. supra-maximal loads where the athlete tries to brake or stop the decent of the load but fails to do so- eg. 110-140% 1RM).
Dependent on the athlete this phase may last anywhere from 4-12 weeks. It’s pretty essential for an athlete to be eccentrically strong in order to get the most out of these isometric training methods. Essentially the “unsuccessful braking” work is a failed isometric muscle action and this preparatory sets the athlete up nicely for a steady progression through the loads during the Iso-Holds. Although the Iso-Holds are an isometric action to the eye, evidence suggests that the Iso-Holds use neural strategies similar to eccentric muscle actions; Iso-Holds therefore become a great segway between the unsuccessful braking work and the Iso-Push.
“Evidence suggests that the Iso-Holds use neural strategies similar to eccentric muscle actions”
While I am progressing from lighter loads- longer TUT (50-65%- 6-10 s) to the heavier load- shorter TUT (70-80%- 2-3 s) Iso-Hold work I start to combine Iso-Push work. Recent evidence suggests that Iso-Hold and Iso-Push exercises utilize different neural strategies and provide a different mechanical and metabolic stress to each other. It’s likely that Iso-Push exercises utilize strategies much similar to concentric muscle actions and there is some evidence to suggest that there is some muscle fascicle shortening occurring during these exercises.
At various stages I will use the force plates during the Iso-Push work to see where my athletes are at and re-quantify my Iso-Hold loads. The Iso-Push work is near-max to max effort work and I normally don’t prescribe less than 90% during the Iso-Push work. I also emphasize rate of force development during the Iso-Push work; the objective is to get to max force as quick as possible. There is evidence that this is more effective at increasing RFD then traditional strength training and the adaptations brought about can be similar to those found in ballistic training options.
Somewhere around early SPP I start to get a bit more specific and start looking at the quasi-isometrics (although all of the isometric work is likely to be “quasi”). Most athletes get on the Iso-Switches and those that are “qualified” move on to the Iso-Catch. However, it’s important here to add I programme the isometrics more around competency then the seasonal demands. I don’t feel the need to move the athlete through the continuum to an exercise that might be considered more specific (i.e. Iso-Holds to Iso-Switches) and appropriate for that part of the season. I consider all of the isometric work specific enough for running that competency becomes the driving force behind progression and programming.
The Iso-Catch exercises are very high intensity exercises on their own and once combined with high loads they can easily become more demanding, in terms of ground reaction and muscle forces, than the event itself. For example, in sprinting GRF’s have been found to be as high as x7 body mass; in an Altitude landing exercise from a 40 cm box an athlete can hit GRF’s of x11 body mass with a stiff single leg landing; but in a knee Iso-Catch (as demonstrated in Figure 5.) with an additional load off +1x body mass an athlete can hit a GRF of nearly x14 body mass (double that of the highest forces found in sprinting). Therefore it’s important to get very strong and competent first and then very gradually load in the higher intensity isometric exercises.
What key positions are you trying to overload?
Alex Natera: Key positions are as close to upright running mid-stance positions as I can get. Ankle angles approximately 5˚ of plantar flexion (if 0˚ is flat foot in standing, knee angles range from 40-45˚ (if 0 degrees is full knee extension) hip angles range from 10-20˚ (if 0 degrees is hip fully extended in a vertical/standing position).
Video Examples: Alex Natera on Instagram: @alex.natera
Figure 1. Athlete demonstrating and Iso-Hold position with no external load while importantly “fixing” their lumbar-pelvic position
Figure 2. Athlete performing the Hip Iso-Switch with a high relative external load
Figure 3. The start position for a hip Iso-Catch- The left (non-working leg) will push into the box to get the system into flight and the Right leg will catch the falling mass with the knee slightly flexed in the position of Figure 1. above
Figure 4. Set position for the knee Iso-Push, using a smith machine with latches reversed to lock the accent of the barbell
Figure 5. A sequence example of a knee Iso-Catch where a landing/catch position is achieved after a short flight phase
Figure 6. Athlete demonstrating the ankle Iso-Hold and Iso-Switch set position
Figure 7. Ankle Iso-Push using reversed latches on the Smith Machine N/B see knee extended in this exercise (unlike in the ankle Iso-Hold, Iso-Switch and Iso-Catch) in order to reduce knee and hip extensors contribution to forces being measured on the force plates
Iso-Hold
Supporting/holding body mass and an external load in a static set position for a period of time. Resistive forces are applied to counter act the gravitational forces and hold the set position. Iso-Holds are normally sub-maximal in nature due to stability issues in being able to resist maximal loading. Smith machine often used to negate stability issues in some exercises.
Iso-Push
Application of very high pushing forces in the set position into an immovable resistance. Objective is to apply force rapidly up to maximal output momentarily before resting. High arousal and motivation required to reach maximal values. Smith Machine used to lock into positions or heavily loaded barbells. Often external feedback required via force plate outputs.
Iso-Switch
Similar to Iso-Holds in set up and loading but exercise is of higher intensity due to its dynamic nature. From an Iso-Hold position the working limb is swapped/switched dynamically with the resting limb. Objective is for the resting limb to build pre-tension before striking the ground or box in order to be able to hit the set position without lag or energy leakage. Work up to similar loading used in the Iso-Holds before progressing.
Iso-Catch
Very high intensity exercise. Higher levels of pre-tension are required in this exercise to hit the set position and avoid energy leakage. The set/working position is consistent with the other progressions however at the commencement of an Iso-Catch repetition there requires a push off to create flight of the system. To overcome the landing forces of the system, higher levels of pre-tension are required.
| Exercise | Additional Load | Duration | Reps | Sets |
| Iso-Holds | Hip- up to 1.5 x System Weight (SW = approx. 33% of BW)
Knee- up to 4 x BW Ankle- up to 2 x BW |
3-10 s | 3-4 | 3-5 |
| Iso-Push | Hip- Max effort (approx. 2.5-3.5 x System Weight)
Knee- Max effort (approx. 3.75-5 Body Weight) Ankle- Max effort (approx. 2.75-3.5 x Body Weight) |
3 s | 2-3 | 2-3 |
| Iso-Switch | Hip- up to 1.25 x SW
Knee- up to 3 x BW Ankle- up to 1.5 x BW |
2-3 s | 3-5 | 2-3 |
| Iso-Catch | Hip- up to 0.75 x SW
Knee- up to 1 x BW Ankle- up to 1 x BW
Hip- up to 1 x SW Knee- up to 1.5 x BW Ankle- up to 1.25 x BW |
1-2 s
0-1 s |
6-8
2-3 |
3-5
2-3 |
Figure 8. Example loading and prescription variables for the isometric exercises
What are the pro’s and con’s of using maximal isometric holds vs. traditional concentric strength work for building speed or explosive movement capabilities?
Alex Natera: Well firstly let me state that traditional lifting is a great way to enhance speed and explosive movement and this sort of work should be the corner stone of a preparatory programme. It certainly is the corner stone of my programmes especially with younger and less trained athletes.
As we know there is a hierarchy in muscle action strength; a concentric contraction being the weakest and the eccentric action being the strongest. One drawback of traditional lifting is that the concentric contraction is the limiting factor in the completion of a lift and because of this both the isometric and eccentric actions do not get stressed or overloaded sufficiently. Although there is an eccentric and potentially and isometric action (if you choose to “pause”) occurring in the traditional lift- they are sub-maximal actions. One common way to apply overload to the traditional lift is to slow the movement down and/or increase TUT but this creates more of a metabolic rather than a neural stress, increases fatigue and ultimately decreases power and force in the concentric portion of the lift- this is obviously not what we want for performance.
Traditional training is also highly fatiguing with high levels of mechanical work performed. It often results in mechanical damage (particularly with eccentric exercise) which causes soreness and requires time for recovery and therefore can negatively affect ensuing training and/or competition. On the flip side isometric training seems to require less recovery time.
As previously mentioned another benefit of isometric training vs. traditional heavy strength training is the ability to generate high rates of force development and therefore promote adaptations similar to ballistic training interventions.
However, the biggest pro for isometric training when it comes to speed or running is specificity. In light of the mechanisms of the spring mass model and ongoing research investigating muscle action, during both steady state and maximal velocity running, we are presented with pretty compelling evidence that a number of lower limb muscles perform in an isometric fashion. The evidence suggests that between touch down and mid-stance, while the system/s “spring” is compressing through the lower limbs, it is in fact the tendons that lengthen while muscle length remains fairly constant. Effectively the muscle produces strong isometric forces in order to stay rigid while the tendon elongates and then snaps back to release energy to toe off and flight.
Figure 9. The spring-mass model applied to running
Can it be helpful to do maximal isometrics without a force plate? Are yielding isometrics an option in this case?
Alex Natera: As stated previously the Iso-Hold and Iso-Push exercises are likely different from a neural, mechanical and metabolic standpoint. For me an Iso-Push is similar to the aggressive resistant action that occurs between touch down and mid-stance so I would not replace an Iso-Push for and Iso-Hold. Also, from an intensity standpoint, you cannot reach the same forces during an Iso-Hold with additional load versus an Iso-Push when you are locked in to an immovable position and able to give it everything you’ve got.
There’s always a way to be able to execute an Iso-Push in a gym if you are creative but of course an Iso-Hold is much easier to set up. The draw back with an Iso-Push is that even with the most motivated and trustworthy athletes it is very hard to get a true maximal effort and this is where a force plate can come in handy to give the athlete a target, keep them accountable and of course to quantify the load/effort and measure the change in isometric strength and the effectiveness of the programme.
Have you seen any strong correlations between force in key isometric positions and improvements in sprint speed?
I have been using isometrics for performance for some time now with sprinters and middle distance runners. My first exposure to isometrics came as a consequence of having to convince a Beijing games medalist to do some strength work. To create buy-in I promised the athlete she wouldn’t have to lift a weight and she would be in and out of the gym in 20 mins. I had a leap of faith! We trained the SL isometric mid-thigh pull as our only strength stimulus for a number of months through the competitive cycle (effectively an Iso-Push exercise). Max. Force increased by 35% and we improved her stride length, contact time and stride frequency at race pace and consequently her vVO2max. The only change/intervention to her programme was the isometric training.
Since then I’ve never had to completely isolate the training to just isometric work. In combination with very specific plyometrics I have found great success improving reactive strength index in sprinters and supporting improvements in max. velocity. One such high level sprinter I worked with had world class acceleration 0-30 m but was decidedly average after transition. He was a real power athlete and didn’t have a lot of spring. Besides some remedial work on hamstrings etc. his whole S&C programme consisted of very specific single leg plyometrics and the isometric training I have outlined. This work supported an excellent track programme and we found improvements in max velocity from 10.87 to 11.52 m/s.
In reality though the isometric work is coupled with strength and power work and also plyometrics, it’s not done as a standalone session anymore except in rare cases. I’m just fortunate to have been presented circumstances where I have managed to try isometrics on their own and this has helped me see its effect on strength and running. Yes a controlled scientific study with a large cohort of elite athletes would be great but where I’m at the moment as a coach is; I’ve used it as a coach out of necessity and I’ve seen it work really well and so I apply it my preparation programmes for runners.
At this stage it’s hard to tell from a pure statistical correlation perspective and I wouldn’t want to sell a method of training based on correlation. However, my strongest athletes isometrically happen to be the best and when the athletes improve their isometric strength they also improve their reactive strength and their running. I have not seen as obvious a trend with for example, jump power and 1RM Squat.
Does the utilization of traditional vs. maximal isometric work change between sprinters and distance runners/endurance athletes?
Alex Natera: I pretty much treat all runners the same to be honest. Both endurance runners and sprinters will do traditional strength & power work and plyometrics and they will supplement this work with the isometric training. Some athletes might do more isometric work than traditional work and some might be the other way around. At some stages some athletes may do no traditional lifting at all and only perform plyometrics and isometric work.
My decisions in the programme will be based on what I see, collect and analyze and learn from the athlete in front of me. However, when an athlete is well trained; they are strong and powerful; they have a high baseline of strength and power; and they can retain their strength and power well- then isometric training and plyometrics tend to be a substantial part of their programme.
About Alex Natera
As a previous S&C coach for both the English Institute of Sport and the South Australian Sports Institute, Alex has done extensive applied work in over a dozen Olympic and Commonwealth games sports, including Sprint Cycling, Canoe-Kayak and Modern Pentathlon. Notably, Alex has played his part in preparing multiple Junior and senior sportsmen for World Championship performances, Olympic Medal successes and World Records throughout his career. Alex holds a Bachelor’s degree in Sport Science, a Master’s degree in Applied Sport Science, the ASCC from the UKSCA and the CSCS from the NSCA and he is currently completing his PhD where he is investigating a novel aspect of power development- high volume power training and repeat power ability.
“Speed Strength, is without doubt a game changer. There are limiting factors and key differences in every athlete. Whether fibre type, ability to use the stretch shortening cycle effectively or even anthropometry. Having the knowledge to use these differences to the benefit of the athlete is a skill that Joel highlights brilliantly in this book.”
-Steffan Jones
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