RESEARCH: Studies shared from 13 to 19 Feb 23

All the studies I've shared are available on the RESOURCES PAGE.



This week's quick summary:

  • Teleoanticipation in all-out short-duration cycling
  • Stretching and it's implications to warm-up, cool-down, ROM, and injury risk
  • Hypoxia on exercise-induced diaphragm fatigue in males vs females
  • Pre-sleep protein supplementation
  • Post-exercise sauna for performance benefits


PACING: Teleoanticipation in all-out short-duration cycling

There are multiple factors that impact pacing and therefore performance (search for "pacing" on my resources page). This study set out to "investigate the effect of all-out cycling test duration on indices of power, anaerobic lactic energy metabolism, perceived exertion and mood."

STUDY DETAILS

  1. Nine physically active men undertook four all-out cycling tests of 5, 15, 30 or 45" from seated stationary start on an ergometer fit with power cranks.
  2. Pacing strategy was apparent in the 45" tests with lower peak and mean power in the initial 10" compared to the 5" and 15" tests.
  3. The first 15" of the 30" and 45" tests revealed lower fatigue indices compared to the 15" tests indicating some pacing in the 30" tests.
  4. An all-out pacing strategy was apparent for at least up to 15", with indicators of dampened power in both 30" and 45" sprints.
  5. Reduced power at the start of all-out long-duration sprints support a central control of at least initial pacing strategy.

PRACTICAL TAKEAWAY

This study showed that even in sprints of a duration as short as 30" the athletes already employed some central control of pacing. The implications here are that even in short intervals the athletes will be applying some sort of strategy and this needs to be taken into consideration when prescribing intervals.
An example where the pacing instruction is included in the interval prescription is fast-start intervals. Another important way to take this into account is to acknowledge that athletes may not achieve the optimal pacing the first time they do a session so it can be valuable to prescribe the same session multiple times to allow them to learn the pacing and intensity that can be achieved.


STRETCHING: Time to move from mandatory stretching? We need to differentiate “Can I?” from “Do I have to?”

I've shared two studies on stretching before: the first showed that a dynamic stretching routine did not impact running economy, but aided performance; while the second showed that dynamic stretching resulted in decreased time to exhaustion. This sort of mixed message appears to be associated with stretching in general. In this review, the authors looked into the research and asked questions about stretching for different goals.

STUDY DETAILS

  1. Warm-up: “Can I stretch in the warm-up?” is “probably yes”; but to the question “Do I have to stretch in the warm-up?” the answer is “maybe not.”
  2. Cool-down: “Can I stretch in the cool-down?” Probably yes, but when performed, post-exercise stretching should eschew high intensities (Behm, 2019). “Do I have to stretch in the cool-down?” Probably not, as evidence suggests it does not enhance recovery.
  3. Range of motion: “Can I stretch to improve ROM?” is Yes. But do I have to stretch to improve ROM? Possibly not, but more comparative research is required, and sports requiring extreme ROM should be considered separately.
  4. Injury prevention: “Can I stretch?” is yes—it probably will not increase injury risk. But the answer to “do I have to stretch?” is “possibly no”—as the likelihood of decreasing the injury risk is contentious.

PRACTICAL TAKEAWAY

My recommendation is that stretching is probably not necessary and that athletes can spend time which they would have used for stretching for other purposes that are more beneficial. However, if stretching is a part of an athlete's routine, it does not appear to be detrimental and I don't believe they would need to make a change to a routine that works for them based on the current research.


ALTITUDE: Effects of hypoxia on exercise-induced diaphragm fatigue in healthy males and females

I have shared many studies on altitude as it is a topic I am particularly interested in (search for "altitude" on the resource page). This is the first study that I can recall that looked into the differences between male and female responses to hypoxia.

STUDY DETAILS

  1. We combined hypoxia with exercise to test the hypothesis that males and females would develop a similar degree of diaphragm fatigue following cycle exercise at the same relative exercise intensity.
  2. Healthy young participants (n = 10 male; n = 10 female) with a high aerobic capacity (120% predicted) performed two time-to-exhaustion (TTE; ~85% maximum) cycle tests on separate days breathing either a normoxic or hypoxic (FiO2 = 0.15) gas mixture.
  3. Males and females had similar TTE durations in normoxia and hypoxia.
  4. Cycling time was significantly shorter in hypoxia versus normoxia in both males and females and did not differ on the basis of sex.
  5. Following the hypoxic TTE tests, males and females experienced a similar degree of diaphragm fatigue compared to normoxia as shown by 20%–25% reductions in transdiaphragmatic twitch pressure (Pditw.
  6. We also observed that females did not fully recover from diaphragm fatigue in hypoxia, whereas males did.
  7. Males experienced a decrease in Pditw post-exercise that extended to 10min post-exercise. Females experienced a significantly reduced Pditw up until the end of the measurement period (60min post-exercise).

PRACTICAL TAKEAWAY

It appears that female athletes took considerably longer to recover from diaphragm fatigue caused by a time to exhaustion test in hypoxia compared to males. Therefore, it is important to consider the training load for female athletes when performing training camps at altitude. Double sessions in a single day should be separated by at least an hour and the fact that the total load from training at altitude may be greater than it is for their make counterparts should be taken into account when planning the training.


PROTEIN: Pre-sleep protein supplementation in professional cyclists during a training camp

I have shared two studies about pre-sleep protein that indicated it was beneficial for whole-body protein synthesis and it increased muscle mass and strength. This study is useful because it looked at a particular condition, a training camp, and tested whether or not pre-sleep protein was beneficial in that case.

STUDY DETAILS

  1. We assessed the effects of pre-sleep protein supplementation in professional cyclists during a training camp accounting for the influence of protein timing.
  2. Participants were randomized to consume a protein supplement (40 g of casein) before sleep or in the afternoon, or an isoenergetic placebo (40 g of carbohydrates) before sleep.
  3. The training camp resulted in a significant increase in training loads, which induced an increase in fatigue indicators and a decrease in performance.
  4. Protein intake was very high in all the participants (>2.5 g/kg on average), with significantly higher levels found in the two protein supplement groups compared to the placebo group.
  5. Protein supplementation, whether administered before sleep or earlier in the day, exerts no beneficial effects during a short-term strenuous training period in professional cyclists, who naturally consume a high-protein diet.

PRACTICAL TAKEAWAY

It appears that athletes who are eating enough to achieve their energy expenditure rates during a training camp will be able to meet their protein needs without supplementation. My recommendation would be to measure protein intake for a few days to make sure that an athlete is achieving their daily protein intake (for athletes 1.6-2.0g/kg/day is a generally accepted range). If the daily intake is being achieved, pre-sleep supplementation is not necessary, however, if not, then pre-sleep protein can be a useful additional meal to increase protein consumption.


HEAT: The effects of post-exercise sauna bathing on 5 and 10km performance in university level track athletes

Heat acclimation is a very important aspect of the training environment that needs to be taken into account both for races in hot and in temperate climates. There are many protocols and interventions shared on my resources page for this topic. This study looked at sauna bathing as an intervention.

STUDY DETAILS

  1. The purpose of this case study was to determine if post-exercise sauna bathing could augment performance in University-level track and field athletes competing in temperate [TEMP] as well as hot and humid environments [HOT].
  2. Athletes completed a total of 16 post-exercise sauna sessions (total time: 600 minutes at ~40-50oC, 5-10% humidity) and 2 heat chamber runs (90 minutes at ~12-15 kmph and a constant38.5oC, 5-10% humidity).
  3. Plasma volume (PV) increased by 13.5% and 4.9% following heat acclimation (HA).
  4. Both athletes had lifetime personal bests in the 5-km in the TEMP competition, posting an average improvement of 1.3±0.8% from their previous personal best.
  5. Of the two athletes, one competed at the HOT competition in 2015 for the 10-km and ran 1:40.4 faster in 2016, reducing their time to completion by 5.0%.
  6. Post-exercise sauna bathing could be a practical and time-efficient method to enhance track and field athlete performance in 5-and 10-km events in both temperate and hot conditions.

PRACTICAL TAKEAWAY

In this case study the benefit from post-exercise sauna bathing was significant. If this is a modality that is available to an athlete then I would highly recommend trying it and including it in the final preparation phase before racing. The protocol from this study was 35-40' at 40-50C with 5-10% humidity for 16 sessions.


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