You can build strength without weights

For athletes struggling with injuries, it may take some time before they can start building strength. The usual recommendation for building strength is that you work out with a load that is 60 per cent or more of what you can manage to lift at one time. But if you have a knee injury, it may be difficult to do heavy squats.

But another method allows you to build strength – without lifting any heavy weights.

The method is called occlusion training, also known as blood flow restriction training.

Thomas Bjørnsen has done research on this training method in his PhD-studies at the University of Agder.

“You can go as low as 20 per cent of the maximum weight you manage to lift and have the same amount of muscle growth as with normal weight training,” says Bjørnsen.

How does it work?

So how does occlusion training make it possible to get stronger without lifting heavy weights?

To start with, just because the weights are lighter, it doesn’t mean the workout is easy. Bjørnsen explains that the key to occlusion training is to have a tight band, or pressure cuff, around the top of the arm or the leg, which limits blood flow to and especially from the muscle being exercised.

The limited blood flow causes the muscle to fill up with blood and various substances, such as lactic acid. This gives an illusion that the lift is much heavier and tricks the brain into believing that the muscle is working harder than it actually is. This enables you to activate larger parts of the muscle, like you do with heavy weights, Bjørnsen explains.

A study published in the International Journal of Exercise Science earlier this year shows that an effective occlusion workout involves doing a total of 75 repetitions spread over four sets, with a load of 30 per cent of what you can manage to lift, and with breaks of 30 to 60 seconds between each set.

Effective for weight lifters and non-exercisers

Occlusion is not a new method. It is based on a Japanese form of training, called Kaatsu, which was established in the 1960s. Since then, the method has been developed and researched to gauge its effectiveness.

Bjørnsen has investigated the effectiveness of this training on individuals who exercise, on those who do not exercise, and on weight lifters.

Overall, he found that occlusion training gave increased muscular strength and muscle growth to the same degree that heavy weight training did.

Bjørnsen says that another interesting finding in his study is that occlusion training provided a complementary effect in conjunction with heavy strength training.

«You have two muscle fibre types: slow-twitch, type 1, for endurance activities, and fast-twitch, type 2, for quick, powerful movements,» he says.

Regular weight training usually has the greatest effect on the type-2 muscle fibre cells. But Bjørnsen explains that when he investigated the effect of occlusion training on weight lifters on the Norwegian national team, they found a greater reaction in the endurance muscle cells.

Overall, this type of training can help make athletes even stronger.

Back to training 3-4 days after surgery

Occlusion training is often used by athletes with injuries or those who want to exercise a muscle without straining the joints.

A person who does weight training, but has knee issues, can use occlusion training to exercise their legs more without straining the knee too much.

But the method can be used by anyone. Bjørnsen believes more physical therapists should use occlusion training to help patients with various injuries to start exercising earlier.

«Some studies show that you can start training as soon as three to four days after a knee surgery,» he says.

Starting workouts early prevents muscle loss and loss of muscle strength, which is common after these types of procedures, according to Bjørnsen.

Caution urged

Nevertheless, Bjørnsen urges caution.

«After all, you’re limiting blood flow. It’s important not to over-tighten the cuff and stop the whole blood supply,» says the researcher.

His research showed that inexperienced people can risk muscle damage.

«The method is generally safe, but it’s really important to start slowly and gradually,» says Bjørnsen.

In a Norwegian review of research on occlusion training, the researchers advised against trying this exercise on your own, without proper control of how much you limit blood flow. The researchers recommend the occlusion method primarily as a way to vary training and not a replacement for regular weight training.

You can achieve a similar effect when exercising at low loads without using pressure bands around the arms or legs. The researchers recommend performing strength exercises to fatigue, with no breaks between repetitions and with short breaks between sets of 15-45 seconds maximum.

Bjørnsen points out, however, that you have to do almost twice as many repetitions to achieve the same effect when you use a low load without occlusion. You can quickly end up doing 150 repetitions at 30 per cent intensity.

«This option is more uncomfortable and can potentially irritate the injury site more after surgery,» he says.

Translated by Ingrid P. Nuse

Reference:

Bjørnsen, T.: Muscular adaptations to frequent low-load blood flow restricted resistance exercise - Application in highly strength-trained athletes. Doctoral dissertation at the University of Agder. (2019)

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Read the Norwegian version of this article at forskning.no