🚴 Why some find sports enjoyable and others exhausting?

Why do some people find sports enjoyable while others find them exhausting? The answer is not limited to physical fitness; our brain plays a determining role in how we judge the difficulty of an effort. This impression, personal to each individual, directly impacts our motivation and performance. An international team of researchers has therefore explored an original avenue to modulate it: the use of vibrations on tendons.

Their recent study equipped volunteers with a portable device that applied vibrations to the Achilles tendon and knee before a stationary cycling session. The objective was to examine whether this stimulation could alter the sensation of effort during exercise.


The observations indicate that participants developed higher power output and showed an increased heart rate after the vibrations, while reporting a sensation of effort comparable to that experienced without stimulation. Consequently, they worked more intensely on a physical level without being clearly aware of it. This observation opens perspectives for helping to overcome the mental barrier of fatigue.

The underlying mechanisms are not yet fully understood, but scientists propose several leads. The vibrations could excite or inhibit neurons in the spinal cord and transform the reactivity of neuromuscular spindles. These alterations change the signals transmitted to the brain, which influences the perception of movement and effort. The brain then receives distinct information, making the exercise subjectively more accessible.

To better understand these results, it is useful to consider two main aspects. First, during exercise, the brain constantly evaluates the difficulty by integrating sensory signals and past experiences. This impression, which is subjective, explains why two people experience the same task differently. Specific brain areas, such as the insular cortex, synthesize data on muscle fatigue or heart rate, and thus determine whether we persist or stop.

This work, still preliminary, has only been tested over short periods of exercise. The team plans to use techniques like electroencephalography to observe the effects on brain activity. At the same time, they are examining the opposite effect, where pain and fatigue amplify the perception of effort. In the longer term, the ambition is to create approaches to encourage regular physical activity, particularly among sedentary individuals.

Deciphering how the brain estimates the relationship between effort and reward could thus enable the adoption of a more active lifestyle. This research, published in the Journal of Sport and Health Science, is part of an international project dedicated to exploring these processes. The next steps will help clarify the potential applications of this work.