🩸🏋️♂️ The physiology of a CrossFit® workout.
💦 In CrossFit®, multiple movements are combined at high intensity. This means that a large amount of muscle mass needs sufficient oxygen to sustain a high working pace.
👍 Nowadays, we have some cool technology that can measure what is happening INSIDE the muscle from a physiology point of view. Or rather from an ‘oxygen supply and demand point of view’.
🤔 What you see here is the readout of a portable Near Infrared Spectroscopy (NIRS) device (@moxymonitor). Using near infrared light, it can detect red blood cells that are fully oxygenated (blood coming from the heart and lungs) and blood cells that are deoxygenated (oxygen used by the tissue). If you put such a device on a large muscle, such as the thigh, you will get a read-out of approx. 60%. This means that 60% of the red blood cells in the tissue are oxygenated.
📈📉 Once you start working out, the muscle oxygenation will drop because demand outpaces supply. Now, when intensity stays low, the heart will pump more oxygenated blood to the tissue and the microvasculature in the muscle will dilate which will lead to a slight increase of muscle oxygenation. See the rowing part in the chart above (first rounds).
When an athlete gets fatigued and intensity is really high, muscle oxygenation will flatten out or even drop. That is what you can see in the latter rounds of the workout shown above (arrows).
🙌 Another cool thing. When the athlete rests briefly in the WOD (fi in between movements), muscle oxygenation shoots up. Also this is clearly visible in the readings above (circles).
✅ Amongst others, NIRS technology can be used to assess thresholds and determine ideal rep schemes in high repetition CrossFit® workouts.
Shoutout to @upside_strength for providing the google docs to analyze the data.
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