RESEARCH: Studies shared from 23 to 29 Jan 2023

All of the studies I've shared (~600 studies) are available on the RESOURCES PAGE.

This week's quick summary:

• role of nutritional elements for sports rehabilitation
• prescription of high-intensity intervals based on oxygen uptake kinetics
• external compression and intramuscular pressure in the lower leg
• mindfulness-based interventions on elite athlete mental health
• nasal dilators and running performance

SUPPLEMENTS: The key role of nutritional elements on sport rehabilitation

STUDY DETAILS

In this narrative review, the authors set out to "define the proper nutritional elements for athletes to meet their needs and facilitate their fast return to sports after surgery or injury". They explain a number of different nutrients, their claimed benefits, and any evidence of support for these claims. Please note that in the extracts below I have included both supplement with claimed benefits and those with evidence.

1. Vitamin D and calcium have been recognized for their contribution to bone healing.
2. Randomized controlled trials did not support vitamin C supplementation in the general population, yet it may be of use in surgery patients, whose vitamin C requirements are increased.
3. Vitamin E supplementation in rats following spinal cord injury improved the hind limb locomotor function, and reduced spinal cord histopathological and morphological damage, while decreasing inflammation.
4. Literature confirms the beneficial impact of supplementary vitamin A in acute wounds and in the healing of injuries caused in bones, burns, intestines, and radiation.
5. Results showed that the intake of creatine offsets the decline in muscle GLUT4 protein during immobilization and increased GLUT4 protein content during rehabilitation, increasing insulin sensitivity, exerting a beneficial effect on glucose homeostasis throughout the body and thus increasing glucose uptake into muscle.
6. Increased collagen production, thickened cartilage, and decreased joint pain are some of the benefits that have been observed, while the use of gelatin and collagen supplements appears to be of low risk.
7. During inflammation, zinc has promotive role for the response of the immune system and the cell proliferation phase, due to its beneficial role during DNA replication in cells in proliferation phase.
8. Selenium has also been found to participate in wound healing as a reducing factor of oxidative stress.
9. Although it is stated that, omega-3 supplementation probably ameliorates muscle loss during immobilization, it has not been proven effective for muscle gain.
10. Curcumin has shown benefits regarding postoperative pain and fatigue.

PRACTICAL TAKEAWAY

The authors conclude: "During various exercise-based rehabilitation interventions, high-quality proteins, fat, vitamins, antioxidants, minerals, and other supplements can play a major role in supporting athletes’ anabolism. Although there are several studies on the ergogenic effect of nutrients and supplements before and during training and competition, there is a research gap on the effectiveness of these nutrients in the rehabilitation of athletes after injury or surgery, in maintaining muscle mass and in reducing rehabilitation time."

Where the current research has gaps, and provided using those supplements is not harmful, I think it can be worthwhile to supplement based on the claimed benefits to take advantage of both placebo effects and any potential benefit that has not been confirmed by researched yet. When an athlete is injured I believe it is critical to be proactive and to try everything at their disposal to return to play as quickly as possible.

INTERVALS: Prescription of high-intensity aerobic interval training based on oxygen uptake kinetics

I've shared many studies on different interval protocols (see the resources page) that use a range of different durations of intervals and rest periods. This study took an interesting approach to determine the effectiveness of intervals.

STUDY DETAILS

1. A commonly measured training response is the analysis of oxygen uptake kinetics, representing the demand of a determined load (speed/work) on the cardiovascular, respiratory, and metabolic systems, providing useful information for the prescription of constant load or interval-type aerobic exercise.
2. There is evidence that during high-intensity aerobic exercise some interventions prescribe brief interval times (<1'), which may lead to a dissociation between the load prescribed and the oxygen uptake demanded, potentially affecting training outcomes.
3. This review explored the time to achieve a close association between the speed/work prescribed and the oxygen uptake demanded after the onset of high-intensity aerobic exercise.
4. The evidence assessed revealed that at least 80% of the oxygen uptake amplitude is reached when phase II of oxygen uptake kinetics is completed (1 to 2 minutes after the onset of exercise, depending on the training status).
5. We propose that the minimum work-time during high-intensity aerobic interval training sessions should be at least 1 minute for athletes and 2 minutes for non-athletes.

PRACTICAL TAKEAWAY

Athletes have a range of different options to manipulate how they perform intervals. This study provides evidence that one of the variables that needs to be carefully considered is the duration of the intervals. My interpretation of the outcome is that designing an interval session that is focused on oxygen uptake demand should have intervals of at least 1' duration if those intervals have an equal rest ratio.

There are other ways to manipulate the demands of intervals, such as short rest (e.g. 7 x 30" fast / 15" easy), and other reasons for doing intervals such as running economy (which do not need to achieve oxygen uptake demands). Therefore, use the evidence from this study with careful consideration of the intent of the intervals.

This tweet resulted in an excellent discussion and a lot of input from coaches and sports scientists. There are details and additional resources that are worth reading in the thread. In addition, I received the paper directly from the author and of course there is much more detail and explanation than can be communicated in an abstract or a tweet. The paper contains detailed perspectives and practical applications so I would recommend reading it in full.

This guidance was particularly relevant: "a potential strategy to improve their performance is to prescribe interval training sessions with long interval (i.e. >1-min) at speeds close to or above CS using recovery times that allow them to maintain a stable speed (performance) in each interval. When the athlete can sustain this speed for for prolonged periods, we suggest to progressively increase the interval duration and/or intensity".

EQUIPMENT: lntramuscular pressure in the lower leg - Studies on chronic exertional compartment syndrome and effects of external compression

STUDY DETAILS

1. This thesis on intramuscular pressure (IMP) in the lower leg is concerned with two topics. The first of these is external compression; more specifically, the effect of compression stockings (CS).
2. The aim of the present thesis was to examine how IMP in the lower leg is affected by external compression in healthy individuals during activity, whether IMP differs with regard to gender and the localization of the compartment in individuals with exercise-induced leg pain, and whether fasciotomy results in a normalization of IMP values in patients with CECS.
3. The study concluded that wearing CS during and after this activity led to elevated IMP and decreased muscle tissue oxygenation, and did not reduce the levels of biomarkers for muscle damage post-exercise.
4. The use of CS during running affects the muscles in the lower leg negatively in healthy individuals.

PRACTICAL TAKEAWAY

The results of this study suggest that there is no benefit, and in fact there is a negative impact on muscle oxygenation, for runners wearing compression socks. Therefore, I would suggest that runners should not use compression socks while running.

A previous meta-analysis that I shared suggested that compression socks do not help recovery either. However, I have not seen any evidence suggesting that wearing compression socks post-exercise is negative so I think it is ok to use them if you feel comfortable and believe they help.

PSYCHOLOGY: The effect of mindfulness-based interventions on elite athlete mental health

STUDY DETAILS

1. Athletes are admired, sometimes even adored, for their physical and psychological strength.
2. Conflicts arise, however, when the very thing athletes are inherently good at (enduring adversity to achieve success) stands in the way of them identifying and acknowledging vulnerability and then seeking mental health support.
3. We included 12 studies that reported relevant mental health assessment scores. We then compared the mental health results of 314 athletes that had undergone a mindfulness-based programme with the results of the 300 athletes that were in the control groups.
4. Overall, athletes that underwent the mindfulness-based programmes reported improved mental health compared to the athletes in the control groups.
5. Significantly reduced symptoms of stress, psychological distress, and anxiety were reported.
6. Both general symptoms of anxiety and competition anxiety reduced, indicating that mindfulness-based programmes could support performance alongside mental health.
7. By developing programmes that are specifically adapted for athletes, and delivering them in group settings with a focus on performance enhancement, it may be possible to broadly improve the mental health of many athletes at once.

PRACTICAL TAKEAWAY

Mindfulness interventions for athletes are valuable and can improve their mental health. I do not have any go-to resources or interventions in this regard, so if you know of something please reply and let me know about it.

EQUIPMENT: Nasal dilator and physiological parameters associated to running performance

STUDY DETAILS

1. The aim of this systematic review was to verify physiological parameters associated to running performance with the use of nasal dilators.
2. Eleven articles were included.
3. There was a difference in favour of the nasal dilator when compared to placebo for maximal oxygen uptake and rating of perceived exertion.
4. The certainty of the evidence was very low.

PRACTICAL TAKEAWAY

While this study suggests that there may be some benefit to nasal dilators, the evidence was "very low". In contrast, there are multiple studies that suggest:

• The external nasal dilator strip showed no improvement in VO2max, HR and RPE outcomes in healthy individuals during exercise.
• External nasal dilator strip (ENDS) does promote nasal route breathing during exercise, but any delay in the onset of oral route breathing during a progressive exercise task appears relatively small.
• Wearing an external nasal dilator does not significantly reduce the work of breathing during exercise.

I do not believe that there is a benefit to using nasal dilators so I would recommend not using them.