RESEARCH: Studies from 1 to 7 Apr 24
Sharing research and insights from coaches, scientists and athletes to help us improve endurance performance.
This week’s quick summary:
Increased oxygen uptake during uphill high intensity intervals
Ketone supplement for mental fatigue in females
Elite swimmers’ training patterns prior to their season’s best performances
Longer disciplined tapers improve marathon performance for recreational runners
Altered pre-exercise CHO availability on RPE during prolonged cycling
INTERVALS: Increased oxygen uptake in well-trained runners during uphill high intensity running intervals
Last week I shared a study that investigated different uphill interval training programs which found that all the different uphill intervals resulted in similar improvements in performance. In this study, the authors set out “to compare the efficacy of running on even terrain versus moderate uphill inclines”.
STUDY DETAILS
Seventeen well-trained runners completed both a horizontal (1% incline) and uphill (8% incline) HIIT protocol.
Uphill running resulted in higher oxygen uptake ( O2mean and O2peak) and accumulated time ≥90% O2max compared to even terrain.
Lactate, heart rate (HR), and perceived exertion (RPE) did not significantly differ between the two protocols.
Moderate uphill HIIT notably increased time spent above 90% VO2max.
The findings suggest that incorporating moderate uphill segments into HIIT sessions can enhance aerobic capacity effectively.
PRACTICAL TAKEAWAY
This study showed that integrating moderate uphill segments into high-intensity interval training sessions can optimise aerobic capacity improvement by increasing time spent above 90% of maximal oxygen uptake. This improvement occurred without significantly increasing perceived effort or physiological strain so the runners made greater improvements for the same effort. My recommendation for athletes is to include uphill intervals in their training. For athletes racing in mountainous terrain, this could be all interval sessions, while for marathon or road runners this could be once every two or three interval sessions.
KETONES: No benefit of ingesting a low-dose ketone monoester supplement on markers of cognitive performance in females
A previous study I shared suggested that ketones may help to maintain mental alertness during an ultramarathon. This is one of the areas that ketones may be beneficial, however there still is no consensus on the best use case for ketones (see all the studies I’ve shared at Supplement - KETONES). In this study, the authors looked at female athletes in particular, aiming “to determine whether ketone supplementation could counteract cognitive decrements induced by mental fatigue in females”.
STUDY DETAILS
Twelve females completed cognitive tests before and after a mentally fatiguing protocol.
Participants ingested either a ketone monoester supplement or a placebo before the protocol in a crossover design.
Ketone supplementation significantly increased blood ketone levels and decreased glucose levels compared to placebo.
Mental fatigue increased perceived cognitive workload and fatigue but did not impair cognitive performance.
Despite changes in blood markers, ketone supplementation did not improve cognitive performance compared to placebo following the mentally fatiguing protocol.
PRACTICAL TAKEAWAY
In this study, ketone supplementation influenced blood markers showing an impact on the subjects’ physiology, but it did not provide cognitive benefits following mental fatigue in females. The results of this study support my recommendation (which has been consistent for a while as more ketone studies are produced) that the benefit of ketones does not yet support the cost of taking them. Therefore I do not recommend that athletes use ketones unless for very specific cases such as during periods of potential overload or overreaching (see study 1 and study 2).
TRAINING: Elite swimmers’ training patterns in the 25 weeks prior to their season’s best performances
I enjoy reading studies using elite athletes and those which look at actual training. This study is an excellent example of that as the authors set out to “investigate the periodization of elite swimmers’ training over the 25 weeks preceding the major competition of the season”.
STUDY DETAILS
A retrospective observational study of 127 elite swimmers (60 male, 67 female) over 20 competitive seasons was performed.
The monitored variables included training intensity levels, general conditioning and strength training hours, total training load, and mean workout volumes.
Latent class mixed modeling identified three distinct total training load patterns.
The fastest sprint pattern consisted of long macrocycles (14-15 weeks) with progressive load increases.
Peak performance correlated with higher training volumes at intensities ≤4 mmol⋅L⁻¹ and >6 mmol⋅L⁻¹.
PRACTICAL TAKEAWAY
In reviewing the training performed, the authors found that elite swimmers focused on progressively increasing training load, with macrocycles lasting around 14-15 weeks. The greatest load was achieved 3-5 weeks before competition and the training intensity was mostly at low intensity (~90% at <4mmol/L). This sort of periodization is consistent with what many coaches recommend so it is useful to have validation of its success with elite athletes. My recommendation is for athletes and coaches to take a long-term approach (with macrocycles of 3-4 months) with careful intensity distribution keeping most of the training low intensity (~85% below the aerobic threshold).
TAPER: Longer disciplined tapers improve marathon performance for recreational runners
Last week I shared a study which showed that a two-week taper with a 40-60% reduction in training volume was optimal. In this study, the authors set out “to determine whether particular forms of taper were more or less favorable to race-day performance” in recreational marathon runners.
STUDY DETAILS
The authors analyzed training data from over 158,000 recreational marathon runners.
The tapers were defined based on decreasing training volume over 1–4 weeks.
Two taper types were identified: strict (progressive decrease) and relaxed (no decrease).
Strict tapers correlated with better performance than relaxed tapers (p < 0.001).
Longer tapers (up to 3 weeks) showed superior performance benefits compared to shorter tapers.
PRACTICAL TAKEAWAY
The results of this research suggest that for recreational runners, adopting a disciplined taper strategy, particularly one lasting up to 3 weeks, can enhance marathon performance. As with my recommendation last week, it is important to note that the effectiveness of a taper is dependent on the training load leading into the taper and the individual athlete’s preferences. However, based on these two studies, my recommendation is for athletes to follow a structured taper for two weeks, cutting down the volume to 50-60% by race week while maintaining training frequency and intensity.
NUTRITION: Effect of altered pre-exercise carbohydrate availability on selection and perception of effort during prolonged cycling
I have shared many studies on carbohydrates which investigate their use before, during, and after training (see Nutrition - CHO). In this study, the authors set out “to investigate how altered carbohydrate availability affects self-selected work rate during prolonged time-trial cycling”.
STUDY DETAILS
Eight endurance-trained men participated in two cycling time-trials after glycogen-depleting exercise and two days of either high (HC) or low carbohydrate (LC) intakes.
Self-selected external power output was similar during the first two hours of exercise between HC and LC conditions.
Despite increased tiredness and reduced carbohydrate oxidation and plasma lactate concentrations in LC, perceived exertion remained consistent throughout exercise.
After approximately two hours, mean power output declined significantly in LC compared to HC, accompanied by reduced cadence, heart rate, and plasma glucose concentration.
These results suggest that initial self-selected work rates in endurance athletes may not be affected by reduced carbohydrate availability, but sustained performance may decline due to decreased glucose availability and increased awareness of dietary carbohydrate restriction.
PRACTICAL TAKEAWAY
This study showed that a low carbohydrate intake prior to a long cycling effort resulted in reduced performance. The cyclists did not initially reduce their pace, but they did see reduced performance after two hours. The authors speculate that the reduction in performance may be in part from dietary perceptions of the athletes along with physiological actions. My recommendation for athletes is to ensure that they eat enough carbohydrates before key training sessions and races. A good starting point is 2g / kg body weight approximately 2 hours before exercise.
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 (345 studies and practical takeaways). Last week, the newsletter covered studies on the following topics:
Sex-related differences in profiles of muscle oxygen saturation
Effects of tapering on performance
Post-exercise muscle glycogen synthesis with glucose and galactose
Pyramidal and polarized training intensity distributions
Effects of different uphill interval-training programs