Why hotter means faster

For high-intensity, short-duration events such as sprinting, a warm-up is a must.

Not only does it help prevent injuries by making muscles more elastic and preparing them for the hard work ahead, warming up can also enhance subsequent performance.

That’s because compared to cold muscles, muscles infused with blood from a warm-up tend to have greater mechanical efficiency due to lower internal friction.

The problem, however, is that in many race situations, it’s nigh on impossible to carry out a pre-race warm-up and then go immediately to the race start. This means that some of the benefits of the warm-up are potentially lost as the muscles cool down in the period between the warm-up and the race start.

But now new British research suggests that there could be an effective strategy for cyclists seeking to maximise the effectiveness of their pre-race warm-up in real-world race conditions.

The science
In the study, scientists from the University of Loughborough investigated the effect of passive insulation versus external heating on thigh muscle temperature and subsequent maximal sprint performance during the period between a sprint-specific warm-up.

To do this, 11 male cyclists completed a standardised 15-minute intermittent warm-up on a cycle ergometer, followed by a 30-minute passive recovery period before completing a 30-second maximal sprint test.

This protocol was completed three times under identical conditions except for the period between the end of the warm-up and the sprint test when the cyclists wore a tracksuit top and either:

* Standard tracksuit pants
* Insulated athletic bottoms (to try and minimise heat losses from the leg muscles)
* Insulated athletic bottoms with integrated electric heating elements to actively heat muscles.

As well as the cyclists’ sprint performance, the researchers also measured temperature in the vastus lateralis muscles (outer thigh) at 1cm, 2cm and 3cm depth prior to and following the warm-up and immediately before the sprint test. In addition, the cyclists’ absolute peak power output was determined.

In a nutshell
The first finding was that the warm-up on the ergometer increased the cyclists’ muscle temperature by around 2.5°C.

The muscle temperature remained elevated when the cyclists wore the bottoms with integrated heating elements but declined when the cyclists were wearing the ordinary or insulated-only bottoms.

More importantly, the researchers also found that when the heated bottoms were worn, the cyclists’ peak power outputs during the sprint test were approximately 9.6 per cent higher and they also produced significantly higher levels of blood lactate (indicating that they had been able to work more intensely).

So what?
The study provides solid evidence that (for sprint events at least) to get the maximum benefits from a warm-up, as much of the heat generated in the muscles as possible needs to be retained before the start.

This means leaving your warm-up as late as possible and then trying to retain that heat, if necessary by using a heat source to maintain the elevated muscle temperature – eg by using heat packs, hot water bottles etc, held against the muscles.

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