Isometrics can be a great addition to any program and may be particularly useful for many athletes involved in reactive sports. Kettlebell sport may be considered a reactive sport and as such, isometric training may increase movement efficiency through improved musculotendinous stiffness. The importance of tendons is often talked about in GS circles. However, very few people talk about training for tendons other than GS training itself. Increased musculotendinous stiffness allows you to better store and utilise elastic energy, increasing your reactive strength. Reactive strength is very important for the counter movement jump (the vertical jump), as the jerk is similar to the counter movement jump. Isometric holds can also be used to improve strength, power and or strength endurance over a specific range of motion. The easiest application is to set up in a posture that is similar to the second or first dip during the jerk. By training these positions, you should improve your specific strength and stiffness. This will in turn allow you to store and use the stretch energy of your dip phase. This is partially achieved through the increase in strength at this position. When this position is achieved, less eccentric or breaking range of motion may be required as increased strength levels allow you to perform the exercise over a shorter distance. Increased stiffness will also allow you to get the most out of your passive structures by transferring energy into the tendons (as opposed to being dissipated by a slow, deep descent). Additionally, isometrics performed with the intention to apply force as quickly as possible have be shown to improve power. We will go into this in more detail in a post on the stretch shortening cycle. I will also do another post on specificity of velocity – a poorly understood concept.
Your personal style may also be a factor in your ability to store and utilise elastic energy. Some people perform a slow longer, or fast shorter dip during their jerk. The faster dip, communicated by some as ‘falling’ into position would create the largest amount of stretch energy. This might be a more natural style for performers with greater amounts of fast twitch fibres. A slow dip many be a natural style for performers with greater amounts of slow twitch fibres. Additionally, having straight legs in the rack position may allow your dip to be more efficient during this phase.
This is a little off topic, but kettlebell sport is commonly compared to middle distance running. Distance runners and sprinters are known to have different muscle architecture and flexibility levels. Sprinters are also known to be quite flexible (and have longer fascicles/sarcomeres in a series, which increases concentric contraction speed, (I will write a post on this at some stage), On the other hand, research has found reduced flexibility may be advantageous for middle distance runners. Jones states: ‘These results suggest that the least flexible runners are also the most economical. It is possible that stiffer musculotendinous structures reduce the aerobic demand of submaximal running by facilitating a greater elastic energy return during the shortening phase of the stretch shortening cycle.’ There are pro and cons to being tight or flexible. With the right training and coaching we may have some ability to consciously regulate your ‘stiffness’. Ten weeks of flexibility training for three 40 minutes sessions significantly increased flexibility, but was found to have a non-significant effect on running economy of a 10 minute time trial. If had to guess I would say ‘stiffness’ may be most useful for jerks at a fast pace or leg speed. It would be really cool to see the differences in muscle architecture between weightlifters and GS athletes.
Isometric contractions of 5-15s are better for maximal strength, but longer may be better for musculotendinous stiffness. In this video I perform a ¼ squat isometric against an unmovable object. This approach allows me to apply maximum force against the bars and is the best method for maximal strength.
With longer holds you may wish to use an external load and maintain your posture. This should help you maintain a consistent force application. I really like using 100+% of 1RM for isometric holds in the squat for 30-60s. This may be one of the best methods to increase the musculotendinous stiffness.
Obviously, you can use rack and overhead holds to improve your rack and fixation positions. You can integrate these into your regular sets by using a slow RPM and focusing on these positions. If you are trying to improve your hand position in fixation, the overhead band hold (resisting internal rotation) may assist you.
I normally work up to an isometric set as my final set(s). This may involve two or more squat sets followed by the isometric set(s). This method is easy to add to the end of a GS session in 10-15 minutes. If you were looking to integrate isometrics into a strength program super setting the concentric/eccentric versions with the isometric is a great method. One of the additional benefits of isometrics is that they cause less soreness compared to eccentric muscle actions. This means, you may be able to train them more frequently and they will have very little negative effects on your subsequent training sessions. Additionally, isometrics are fantastic for tendon issues and may be a powerful way to reduce pain and discomfort with this type of overuse injury.