SESSION NOTES: Relative Stamina (814)

Isometric training is a style of exercise that involves holding a static position (as opposed to concentric training, where the muscle goes through a ‘shortening contraction’ or eccentric training, where the muscle goes through a ‘lengthening contraction’.

There are a range of benefits of isometric training that are unique to this style of muscle contraction type.

This session contains an even balance of ‘pull’ and ‘push’ based exercises, with a heavy requirement to stabilise and brace the muscles involved in flexing the trunk. There is also a lower body stamina movement.

The push movements and the pull movements alternate, which means there is some degree of recovery between movements of a similar type to maximise volume.

The lower body movement (in addition to providing a benefit to localised muscular stamina and incentivising big, unbroken sets) creates a ‘blood shunting’ effect which will improve cardiorespiratory endurance. This blood shunting means there will be a cardiorespiratory benefit, and you will have the added challenge of training with high levels of hydrogen ions (the acid feeling you get from high intensity exercise) in your system, and not just under localised muscular fatigue.

This session is a form of resistance training that provides a stimulus with lighter loads and higher volume (time under tension) than an absolute strength or power based session. While the high levels of fatigue in this session makes it less effective to increase strength and power, it will improve your stamina – the ability of your muscles to resist fatigue.

As this session requires you to go close to failure, you will achieve a very high level of motor unit activation. Motor units are the motor neurons (nerves) and the muscle fibres they ‘switch on’. When we contact a muscle, we are in fact only contracting a small number of muscle fibres. We can’t turn a muscle fibre ‘half on’, it’s either ‘on’ or ‘off’. When you stop a set before failure, you are failing to maximise the number of fibres you’re activating. By going close to failure in the sets in this session, we are maximising the number of motor units we’re activating, which means we’re able to get a lot of effect from a relatively small amount of work (albeit at a higher intensity).

As a result of this style of session, you will experience changes in blood chemistry, including favourable effects on cholesterol, blood glucose, triglyceride and lipid levels.

In terms of body composition, isometric movements are an important part of an exercise program for increasing lean muscle. Muscle is a metabolically active tissue, so increasing it will maximise how much energy your body burns at rest. This makes it an effective session to reach healthy levels of body fat, both visceral fat (around the organs) and subcutaneous fat (under your skin). After this session, your body will go through a prolonged state of ‘EPOC’ (excess post- exercise oxygen consumption), meaning you’ll continue burning energy long after you finish training – further aiding healthy body composition.

Isometric training has been shown to have the most powerful effect on reducing systolic blood pressure, diastolic blood pressure, and mean arterial pressure.

The session will improve body control and awareness due to the ability to make slight adjustments to body shape to achieve an optimal position. This will have positive effects on postural awareness and control.

In terms of benefits to the joints, the static holds will improve joint stability which can reduce pain, and the lack of movement means that this is an effective training type for people who need to strengthen joints but for whom movement aggravates joint pain. Isometric work is not only effective as a way to exercise to avoid pain, but has also been shown to reduce pain levels.

The high amount of time under tension in this session trains the ability of your muscles to resist fatigue – increasing their stamina. This comes from improvements in the efficiency of slow twitch (fatigue resistant) muscle fibres.

As a further result of the sustained contractions, this session will increase the mitochondrial density in your muscle cells, allowing them to more efficiently convert energy into fuel. This means you can sustain higher levels of muscle contraction before fatigue or failure.

The higher volumes will also increase capillary density in your muscles, allowing for efficient delivery of oxygen and fuel, and removal of waste products (further adding to the fatigue resistance).

Due to the progressive fatigue from isometric training, you will experience a very high level of recruitment of motor units (motor neuron plus muscle fibre), leading to a very high percentage of total muscle fibres trained.

The exercises in this session also target what is often a weaker part of the movement. Even though the holds are static, this ‘weak point training’ can improve the overall strength of the full movement by strengthening the weakest part. The research points to increases in strength up to 15 degrees on each side of the training angle.

The static holds will improve joint stability to increase the ability to efficiently move loads.

The aim of this session is to complete the total required static hold time as quickly as possible. This means big, unbroken sets should be the aim (though if you’re able to hold more than 30 seconds in the first round of each, you should scale the movement to increase difficulty). The ‘penalty reps’ of the lower body movement should incentivise these larger sets (which will give the desired benefit of the session).

Rest should be kept to a minimum, as the three movements have very little overlap/interference, so as one muscle group is working, the other can be resting.

If you have scaled the movement correctly, you should be able to hold each exercise for a similar amount of time.

You should feel like it is difficult to maintain each static hold, and you should be going close to failure each round. ‘Shaking’ during the movements is common – it’s caused by a depletion of the chemical messengers that carry the signals between nerves and muscle cells. Because all motor units don’t fire at once, shaking can occur.

If you’re able to maintain big sets, the legs won’t be too much of a limiting factor. Smaller sets however will result in a lot of lower body fatigue and burning.

Although the primary focus of this session is localised muscular stamina, you will also get a cardiorespiratory effect, so you may be breathing harder than you expect.

Scale so movements are similar difficulty and so you can do between 20s and 30s in the first round of each.

Incorrect scaling can mean that you end up with one exercise being easier than the other. Ensure both are similar difficulty.

This session should be more ‘upper body’ than ‘lower body’ focussed, so push for big, unbroken sets to ensure that a sufficient level of upper body fatigue is achieved and that the lower body movement doesn’t become the limiting factor.