RESEARCH: studies shared from 20 to 26 Mar 23

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



This week's quick summary:

  • Detraining in professional cyclists during lockdown
  • Protein supplementation and strength training
  • Regional sweat evaporation and ventilatory responses
  • Perceptions and use of recovery strategies
  • Muscle protein response to a plant-derived protein blend


DETRAINING: Training load and performance impairments in professional cyclists during COVID-19 lockdown

A previous study I shared showed that endurance performance in general populations could be maintained up to 15 weeks with volume reductions of 33-66% as long as exercise intensity was maintained. However, another study showed that in recreational athletes after 4 weeks of detraining, there were significant reductions in plasma volume (PV), left ventricular (LV) wall thickness, LV mass, and right atrial area. In particular, older athletes lose fitness much more quickly. And finally, one week of sedentary lifestyle substantially lowered daily myofibrillar protein synthesis rates.

This study is interesting because it looked at the impact of reduced training in professional athletes. The report aims to inform about the changes in training volume and intensity distribution and their effects on functional performance due to a 7-week home-confinement period in professional road cyclists from a Union Cycliste Internationale Pro Team.

STUDY DETAILS

  1. A total of 18 male professional cyclists were monitored during the 10 weeks before the lockdown (outdoor cycling) and the 7-week lockdown (indoor cycling turbo trainer).
  2. Total training volume decreased 33.9% during the lockdown. Weekly volumes by standardized zones (Z1 to Z6) declined between 25.8% and 52.2%, except for Z2.
  3. There were large reductions in best 5-minute and best 20-minute performance with losses between 1% and 19% in all the cyclists.
  4. Total indoor volumes of 12 hours per week, with 6 hours per week at low intensity (Z1 and Z2) and 2 hours per week at high intensity over the threshold (Z5 and Z6), were insufficient to maintain performance in elite road cyclists during the COVID-19 lockdown.

PRACTICAL TAKEAWAY

Detraining occurs quickly in professional cyclists even if they maintain ~65% of their normal training volume and maintain their training intensity. While significantly reduced training may be sufficient to maintain fitness in the general population, there will still be detraining consequences. My recommendations to limit detraining (either during an off-season or perhaps in a period where training is not a priority) are to maintain 60% of weekly training volume, to include one to two high-intensity sessions, and ideally to limit this period to less than four weeks.


PROTEIN: Neither chia flour nor whey protein supplementation further improves body composition or strength gains after a resistance training program in young subjects with a habitual high daily protein intake

Previous studies I've shared have shown the benefits of protein post-exercise and pre-sleep for both strength and endurance performance (search for "protein" on my resources page). This study aimed to "compare the potential additional effect of chia flour, whey protein, and a placebo juice to resistance training on fat-free mass (FFM) and strength gains in untrained young men".

STUDY DETAILS

  1. Eighteen healthy, untrained young men underwent an 8-week whole-body resistance training program, comprising three sessions per week.
  2. Subjects were randomized into three groups that after each training session consumed: (1) 30 g whey protein concentrate containing 23 g protein (WG), (2) 50 g chia flour containing 20 g protein (CG), or (3) a placebo not containing protein (PG).
  3. Resistance training increased fat-free mass (FFM) and the 1 RM for each of the strength tests similarly in the three groups.
  4. FFM increased by 2.3% in WG, by 3.6% in CG, and by 3.0% in PG, and 1 RM increased in the different strength tests in the three groups with no difference between PG, CG, and WG.
  5. In conclusion, neither chia flour nor whey protein supplementation elicited an enhanced effect on FFM and strength gains after an 8-week resistance training program in healthy, untrained young men consuming a habitual high protein mixed diet (>1.2 g/kg/day).

PRACTICAL TAKEAWAY

While protein supplementation has often shown to be beneficial for performance, this study showed that there is no additional benefit when consuming a diet that already contains sufficient protein. This is similar to a study I shared that showed there was no benefit of additional protein ingested prior to sleep for cyclists on a training camp (in that study the cyclists were consuming 2.5g/kg/day of protein).
For athletes already eating sufficient amounts of protein there is no need to supplement with extra recovery shakes or pre-sleep protein. Athletes should first check their daily protein intakes before supplementing.


PHYSIOLOGY: Inhibiting regional sweat evaporation modifies the ventilatory response to exercise

Sweating is an important mechanism in cooling in hot climates. This study set out to determine "the impact of changing the effective body surface area for sweat evaporation".

STUDY DETAILS

  1. Ten healthy adults (9 Male, 1 Female) performed eight exercise trials cycling at 6 W/kg of metabolic heat production for 60 minutes.
  2. Four conditions were used where the effective body surface area for sweat evaporation (BSAeff) corresponded to 100, 80, 60, and 40% of BSA using vapor impermeable material.
  3. Four trials (one at each BSAeff) were performed at 25°C air temperature, and four trials (one at each BSAeff) at 40°C air temperature, each with 20% humidity.
  4. At 25°C, the V̇E/V̇CO2 slope was elevated by 1.9 and 2.6 units when decreasing BSAeff from 100 to 80 and to 40%.
  5. At 40°C, V̇E/V̇CO2 slope was` elevated by 3.3 and 4.7 units, when decreasing BSAeff from 100 to 60 and to 40%
  6. Overall, we show that impeding regional sweat evaporation increases the ventilatory response to exercise in temperate and hot environmental conditions, and the effect is mediated primarily by increases in mean body temperature.

PRACTICAL TAKEAWAY

Inhibiting sweating leads to higher body temperatures which directly impacts ventilatory rates. Therefore, ensuring that clothing and equipment does not inhibit sweating is important to ensure optimal performance in hot conditions. My recommendation is to choose light, sweat-wicking clothing and also to not cover the skin in areas where this is possible (legs and arms for example).


RECOVERY: Perceptions and use of recovery strategies: Do swimmers and coaches believe they are effective?

I've shared a broad range of recovery strategies on my resources page. In this study, the authors aimed "to investigate swimmer’s use and coach prescription of recovery strategies during training and competition while examining perceived challenges, barriers, and beliefs in the importance of their effectiveness".

STUDY DETAILS

  1. Thirty-seven male and 45 female sub-elite to elite swimmers (age 18 ± 3 y), and 4 male and 6 female coaches (age 40 ± 9 y) completed an online, 78-item recovery strategy survey.
  2. Most recovery strategies were used and prescribed more during competition.
  3. Swimmers reported active recovery as the most effective recovery strategy (44%), whereas coaches rated sleep or napping (40%).
  4. Swimmers used, and coaches prescribed, recovery strategies more during the competition, highlighting the discrepancies in use between training and competition.

PRACTICAL TAKEAWAY

As a coach, I would also have chosen sleep as the most effective means of recovery. However, it is important to be cognizant that athletes rated active recovery as the most effective means and to incorporate this into a plan if it can help both physically and perceptually. I would also recommend incorporating more recovery into training periods to ensure that adequate adaptation is occurring for the training that is being performed.


PROTEIN: The muscle protein synthetic response to the ingestion of a plant-derived protein blend does not differ from an equivalent amount of milk protein in healthy young males

A previous study I shared showed that whey protein was superior to soy protein for improving body composition. In this study the authors "aimed to compare postprandial muscle protein synthesis rates following the ingestion of 30 g milk protein with a 30 g blend combining wheat, corn, and pea protein in healthy young men".

STUDY DETAILS

  1. 24 young males (aged 24 ± 4 y) received a primed continuous l-[ring-13C6]-phenylalanine infusion after which they ingested 30 g milk protein (MILK) or a 30 g plant-derived protein blend combining 15 g wheat, 7.5 g corn, and 7.5 g pea protein (PLANT-BLEND).
  2. MILK increased plasma essential amino acid concentrations more than PLANT-BLEND over the 5 h postprandial period.
  3. Ingestion of both MILK and PLANT-BLEND increased myofibrillar protein synthesis rates, with no significant differences between treatments.
  4. The muscle protein synthetic response to the ingestion of 30 g of this plant-derived protein blend does not differ from the ingestion of an equivalent amount of a high-quality animal-derived protein.

PRACTICAL TAKEAWAY

Plant-derived protein can be as effective as animal-derived protein for muscle protein synthesis. However, I would note that to achieve the same benefit requires a blended plant protein combination. I have not yet seen recovery shakes or products that offer this yet (typically pea protein or soy protein options are available, but not blends). For athletes who want to follow a plant-based diet, it is important to ensure that they have a range of different plant proteins in their diet.


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