RESEARCH: Studies from 17 to 23 Mar 25
Sharing research and insights from coaches, scientists and athletes to help us improve endurance performance.
This week’s quick summary:
Maintaining power output with accumulating levels of work done
Fibre: the forgotten carbohydrate in sports nutrition recommendations
A comparison of three different warm-ups on 800m running performance
Training wearing thermal clothing and training in hot ambient conditions
Achieving energy balance with a high-fat meal
PHYSIOLOGY: Maintaining power output with accumulating levels of work done is a key determinant for success in professional cycling
Success in professional cycling depends on multiple performance factors, but the ability to sustain high power output under fatigue is crucial. Previous research highlights the importance of maximal mean power output (MMP) for performance, yet its decline with increasing workload remains less understood. In this study, the authors aimed to “examine how prior work done influences MMP and, consequently, success in professional cycling”.
STUDY DETAILS
Data from 26 professional cyclists across 85 seasons (2012–2019) were analysed, with riders classified as climbers or sprinters and grouped by success level based on procyclingstats-points (PCSpoints).
MMP for 20 min, 5 min, 1 min, and 10s relative to body weight was measured across different levels of accumulated work (0–50kJ/kg).
Performance declined with increasing workload, but more successful cyclists (CAT.1) maintained higher power outputs under fatigue compared to less successful cyclists (CAT.2).
CAT.1 climbers showed a smaller decline in 20- and 5-min MMP after high workloads than CAT.2 climbers.
CAT.1 sprinters showed a smaller decline in 10s and 1 min MMP after high workloads than CAT.2 sprinters.
PRACTICAL TAKEAWAY
This study showed that the ability to sustain power output under fatigue differentiates successful from less successful cyclists. My recommendation is to monitor power outputs after certain workloads to identify where targeted training might help improve a cyclist’s performance. Climbers should emphasise maintaining high power in 5-20 min efforts after extensive work, while sprinters should prioritise short, high-intensity bursts under fatigue.
RELATED RESEARCH
NUTRITION: Fibre: the forgotten carbohydrate in sports nutrition recommendations
Carbohydrate intake is well established in sports nutrition, yet fibre is often overlooked. Athletes commonly adjust fibre intake to manage gastrointestinal (GI) comfort, body composition, and performance, but fibre also plays a key role in overall health, particularly when combined with high protein intake. In this opinion paper, the authors aim to “ensure that fibre is not forgotten as a nutrient in the athlete’s diet”.
OPINION PAPER DETAILS
The study highlights that fibre intake in athletes is often below 20g/day, which may impact gut microbiome stability, intestinal health, and metabolic function.
A gradual increase to ~30g/day, including ~2g of beta-glucan, over six weeks is proposed to improve microbiome diversity and support gut barrier function.
Short-chain fatty acids, produced by fibre fermentation, contribute to overall metabolic health and may influence athletic performance.
Fibre intake should be strategically adjusted based on training demands—reducing fibre to avoid GI distress around key training sessions or competitions, and increasing it for long-term health benefits.
Further research is required, but current evidence supports fibre as an essential, modifiable component of an athlete’s diet.
PRACTICAL TAKEAWAY
In this paper, the authors explain that athletes should monitor fibre intake and aim for ~30g/day to support gut health and metabolic function. Gradual increases over six weeks can help adaptation. My recommendation is that athletes should adjust fibre intake based on training load and competition schedule to maintain GI comfort while maximising long-term health benefits.
RELATED RESEARCH
PHYSIOLOGY: A comparison of three different warm-ups on 800m running performance in elite division I track athletes
Warm-ups are often based on what athletes were taught when they first started running or on trying to fit something in the difficult logistics before a track race starts. In this study, the authors aimed to “compare three different warm-up protocols on 800m performance in elite collegiate athletes”.
STUDY DETAILS
Thirteen Division I middle-distance runners (seven males, six females) from the Southeastern Conference participated in this study.
A randomised, cross-over design tested low, medium, and high-volume warm-ups over three weeks on an outdoor track.
Performance was measured using 800m race times, with statistical analysis conducted through a 2 (Sex) x 3 (Warm-Up Protocol) mixed-factor ANOVA.
A significant main effect of warm-up volume was found, but sex did not influence results.
Post-hoc tests indicated that high-volume warm-ups led to the best performance, followed by medium-volume warm-ups, with low-volume warm-ups resulting in the slowest times.
PRACTICAL TAKEAWAY
The results of this study suggest that 800m runners should incorporate a high-volume warm-up before races to maximise performance. A medium-volume warm-up is better than a low-volume one but still suboptimal. My recommendation for athletes is to practise a race-specific warm-up in training and to make sure that it is repeatable before all their races. The high-volume warm-up in this study included 2 x 100m, 200m, and 300m at race pace.
RELATED RESEARCH
HEAT: Training wearing thermal clothing and training in hot ambient conditions are equally effective methods of heat acclimation
Research has shown that heat acclimation can improve endurance performance in hot conditions. Methods such as training in high temperatures and wearing thermal clothing have been proposed, but their relative effectiveness remains unclear. In this study, the authors aimed to “determine whether training in a heat chamber, wearing thermal clothing, or combining thermal clothing with hot water immersion would yield different physiological and performance outcomes”.
STUDY DETAILS
34 cyclists completed one of three interventions: training in 35°C, training while wearing thermal clothing, or training while wearing thermal clothing plus post-exercise hot water immersion.
Each intervention involved 50 minutes of daily cycling for 10 days, with an additional 25-minute hot water immersion for one group.
Physiological measurements included hemoglobin mass, blood lactate concentration, sweat rate, heart rate, and core temperature at rest and during exercise.
All three interventions improved 30-minute all-out cycling power in 35°C by ~10% without significant differences between groups.
No differences were observed in blood lactate response, perceived exertion, or sweat rate among interventions.
PRACTICAL TAKEAWAY
The results showed that heat acclimation improves performance in hot conditions, but training in 35°C, wearing thermal clothing, or adding hot water immersion all produce similar results. Therefore, athletes can choose the most convenient method based on available conditions. My recommendation is for athletes to include heat training throughout the year. In this case, it may be easiest to use thermal clothing as that should always be available and is repeatable in different seasons.
RELATED RESEARCH
NUTRITION: Achieving energy balance with a high-fat meal does not enhance skeletal muscle adaptation and impairs glycaemic response in a sleep-low training model
Previous research has demonstrated that low carbohydrate availability during training enhances endurance muscle adaptation. However, the impact of energy balance achieved mainly through fat intake in this context remains unclear. In this study, the authors set out to “determine if achieving energy balance post training with high-fat (EB-HF) acutely enhances the adaptive response in low muscle glycogen training compared to low-fat approaches”.
STUDY DETAILS
9 well-trained male cyclists participated in this study using a crossover design.
Participants completed a "sleep-low" protocol, depleting muscle glycogen through cycling and reaching a set energy expenditure.
Post-exercise, they consumed protein-matched meals to achieve energy balance (EB-HF) or partial energy deficit (ED-LF), with EB-HF containing more fat.
Muscle glycogen decreased from 350 ± 98 to 192 ± 94 mmol (kg dry mass)−1 with no treatment effect.
Plasma glucose and insulin responses were higher in EB-HF, impairing glycaemic control after the recovery drink.
PRACTICAL TAKEAWAY
These results showed that achieving energy balance with a high-fat meal following exercise in a ‘sleep-low’ model does not improve skeletal muscle adaptation and may impair glycaemic control the next morning. For optimal recovery and adaptation, a balanced approach to macronutrient intake may be more beneficial than relying on high-fat meals alone. My recommendation for athletes is to ensure that they achieve an energy balance after hard training sessions without worrying too much about the composition of that meal as none of the different options appeared superior.
RELATED RESEARCH
Quick summary from last week’s paid newsletter
Paid subscribers receive a newsletter every week and have full access to all newsletters listed in the archives (595 studies and practical takeaways). Last week, the newsletter covered studies on the following topics:
CHO supplementation during short-term energy deficit
Effect of plyometric jump training on skeletal muscle hypertrophy
A ketone ester drink increases post-exercise muscle glycogen synthesis
Sex differences in uphill performance
Hypoxia reduces sleep quality without impacting next-day exercise performance
