Introduction. The last few posts have covered the topic of assessments, and how Moxy/NIRS devices can be used to gain insight into how the muscle is responding to different loads in real-time. The most common assessment that uses Moxy is the 5-1-5 assessment. Through a progressive increase in exercise intensity with dispersed rest periods this assessment is designed to determined which system (cardiac, pulmonary, and/or skeletal muscle) is most limiting to performance. The second assessment used is a progressive strength test. The goal of this test is to evaluate the blood flow/volume response (tHb) during progressively harder weight-lifting. Upon completion the athlete gains insight to the rep ranges necessary to best elicit different adaptations (strength, hypertrophy, endurance). The above two tests are designed to evaluate endurance and strength limitations, however, the major drawback to these assessments is that they are not very sport specific. Therefore, this post will discuss a repeat desaturation protocol which can be used to evaluate team sport athletes whose sports require repeated sprints. While this style of assessment is best suited for sport specific evaluation, it can still be used for sports that do not use repeated sprints in competition (e.g. many endurance sports). This assessment is useful because it provides insights to how well an athlete responds and recovers to high intensity bouts.
Purpose. Briefly, the repeated desaturation protocol is designed to have an athlete repeatedly desaturate muscle oxygen (SmO2) through a 10-30s sprint, followed by full recovery to see how their physiology responds to repeated bouts of all-out work.
Equipment. For this test you will need the following:
- Moxy monitor placed on a large prime mover for the exercise (e.g. vastus lateralis)
- Cycle ergometer, rowing machine, assault bike, treadmill, or turf field/track
- Watch or phone to visualize SmO2 response
- Heart rate monitor (optional)
Set up/Design: When designing this assessment be as sport specific as possible. For example if the athlete is a soccer player have them run repeated (10-20 s sprints), on a turf or grassy field. If they are a cyclist have them complete testing on a cycle ergometer preferably their own bike. For Crossfit/multimodal athletes many different set-ups can be used but Evan Piekon at Training Think Tank recommends to use a rower/assault bike with 20s sprints followed by 1 minute of rest.
Termination point. The assessment is terminated when SmO2 cannot be depleted to same extent as previous sets. Or when tHb and/or SmO2 recovery baselines cannot be reached or when there is a steep drop off in wattage/speed even though recovery SmO2 is reached.
Example Protocol. In this example, the athlete is primarily a cyclist. Therefore this assessment was completed on a stationary bike. I instructed them to go hard (>500 w) for 20s, followed by a 1 minute spin rest. In this test, the rest is important but it is not as critical to have the athlete be completely still as it is for the 5-1-5 assessment. The athlete completed 9 reps of 20s hard 1 minute rest. For the first three reps the athlete maintained intensities above 500w, for the next three they were instructed to pedal above 550w, and for the final three they were instructed to pedal above 600w. The test was stopped after the 9th rep because SmO2 was not able to be depressed to the same level as previously seen. Furthermore, the athlete was getting extremely tired. To test if the athlete could still fully desaturate after extremely hard efforts the test finished with 15s all out. This was to get an idea of how close to max the athlete was operating during their sets. Indeed, the athlete was able to desaturate to 15% which is lower than the 20-25% seen during the intervals.
Summary/Conclusion. Other assessments that have been discussed are designed to test athletes limiters for both endurance and strength. While extremely valuable information can be gleaned from these tests, they aren’t designed for team sport athletes. Therefore, the repeated desaturation protocol is a good assessment to evaluate how a team sports or mixed multimodal athlete will respond to repeated all-out bouts of exercise. In the next post an example of the desaturation protocol will be analyzed from the example protocol above.