RESEARCH: Studies from 29 Apr to 5 May 24
Sharing research and insights from coaches, scientists and athletes to help us improve endurance performance.
This week’s quick summary:
Vitamin C for musculoskeletal healing and reducing oxidative stress
Understanding of ultra-endurance running performance
Effect of marathon running on the lower extremity kinematics
Do poles save energy during steep uphill walking?
CHO supplementation and the influence of breakfast on fuel use in hypoxia
SUPPLEMENT: Efficacy of vitamin C supplementation on collagen synthesis and oxidative stress after musculoskeletal injuries
Musculoskeletal injuries are issues that runners often have to deal with (see the prevalence of injuries in mountain running races) and this type of interruption can have a negative impact on performance. Finding ways to avoid injuries or to mitigate the impact of these injuries is important. In this study, the authors set out “to evaluate the efficacy of vitamin C in promoting musculoskeletal healing and reducing oxidative stress”.
REVIEW DETAILS
A systematic review was conducted which initially identified 286 articles.
Ten articles met inclusion criteria after screening.
The results from preclinical studies showed accelerated bone healing with vitamin C supplementation.
Increased type I collagen synthesis was observed in preclinical tendon studies.
Clinical studies showed no significant differences in fracture healing rate or functional outcomes with vitamin C supplementation.
PRACTICAL TAKEAWAY
The results of this review suggest that vitamin C supplementation shows promise in accelerating bone and tendon healing, as well as reducing oxidative stress post-injury. As this study was a review of other research, there was a large range of doses of vitamin C, however, for the study that provided the most benefit of recovery from musculoskeletal injuries the dose was 500mg twice daily for 3 months. My recommendation for athletes who suffer an injury is to try supplementing with 500-1000mg/day of vitamin C during their recovery.
PHYSIOLOGY: Limits of ultra: towards an interdisciplinary understanding of ultra-endurance running performance
I have shared some studies that investigate the determinants of performance and the characteristics of ultramarathon runners (see Physiology - PREDICTING PERFORMANCE). While there is some research in this area, there is a lot of work still to be done. In this paper, the authors set out “to comprehend the challenges and limitations of ultra-endurance running (UER) to enhance performance”.
REVIEW DETAILS
Evolutionary Perspective: Humans possess evolutionary adaptations advantageous for covering long distances, but modern UER levels exceed ancestral capacities.
Physiological and Psychological Systems: Thermoregulation, oxygen delivery, running economy, biomechanics, fatigue, and the digestive system are critical. Strategies include pacing, heat acclimation, hydration, nutritional approaches, and goal setting.
Minimising Costs: Focus should be on reducing running cost, lower limb damage, and muscle fatigue for optimal UER performance.
Core Body Temperature: Sustaining a suitable core temperature is vital, aided by pacing strategies and personalized hydration plans.
Psychological Factors: Coping with complexity, setting goals, and managing perceived effort are crucial for UER success.
PRACTICAL TAKEAWAY
This paper is useful in providing guidance on specific considerations of ultramarathons that athletes can focus on. The authors explain that to excel in ultra-endurance running, athletes should focus on minimising physical costs, managing core body temperature effectively, and adopting tailored psychological strategies to cope with the demands of the sport. My recommendation for athletes is to look into each of these aspects of their preparation:
minimising physical costs - consider equipment such as shoes and poles;
managing core temperature - prepare for the heat and choose clothing to take with during the race; and
cope with psychological factors - do mental training and use self talk.
PHYSIOLOGY: The effect of marathon running on the lower extremity kinematics and muscle activities during walking and running tasks
This study looked into the impact of running a marathon on the form and biomechanics of runners. The authors set out “to investigate whether differences in knee and hip kinematics and lower extremity muscle activities exist in recreational runners before and after a marathon”.
STUDY DETAILS
12 recreational runners participated.
Kinematics and muscle activities recorded during walking (5km/h) and running (10km/h) within 24 hours before and within 5 hours after the marathon.
Significant decrease in peak knee flexion during walking (p = 0.006) and running (p = 0.006) after the marathon.
Significant increase in peak hip internal rotation during walking (p = 0.026) and running (p = 0.015) after the marathon.
These changes may elevate the risk of Patellofemoral pain syndrome (PFPS) injury.
PRACTICAL TAKEAWAY
The results of this study show that post-marathon, recreational runners exhibit decreased knee flexion and increased hip internal rotation in their running gait, potentially heightening the risk of PFPS injury. My recommendation for athletes after a demanding event is to use caution in returning to training. Easing back into the training slowly with short sessions and performing mobility exercises until normal mobility and function return will help prevent any risk of injury when starting a new training cycle.
EQUIPMENT: Do poles save energy during steep uphill walking?
It is common to see trail runners using poles in ultra-marathons and also during very steep vertical kilometer races. The general perception is that poles are helpful, but there is little research on this topic. In this study, the authors set out “to determine whether poles offer tangible benefits in steep terrain”.
STUDY DETAILS
Fourteen mountain runners participated in walking trials on a treadmill.
Participants walked for 5 minutes at varying inclines, with and without poles.
Results showed lower energy expenditure with poles at inclines of 25.4°, 29.8°, and 35.5°.
Ratings of perceived exertion (RPE) were significantly lower with poles at several inclines.
Pole use did not significantly affect blood lactate concentration (BLa), but RPE was notably lower with poles.
PRACTICAL TAKEAWAY
The authors show that using poles during steep uphills may offer modest energy savings even though it significantly reduces perceived effort. My recommendation for athletes aiming for their best performance in very steep races (>25° such as the vertical kilometer at Fully) is to use poles. For middle distance races with less steep inclines, perhaps up to a marathon distance, poles are probably less beneficial unless the athlete is very proficient with them so I would leave this up to the athlete to make their own decision. For ultramarathons, even though the cost of running does not show much benefit for using poles, the benefit from reducing muscle damage and from lower RPE means I recommend poles for these distances too.
NUTRITION: Carbohydrate supplementation and the influence of breakfast on fuel use in hypoxia
A previous study I shared provided recommendations for nutrition at altitude which was a general guide looking on overall nutrition practices at altitude camps. In this study, the authors set out “to understand how carbohydrate intake before or during exercise in hypoxia influences fuel use”.
STUDY DETAILS
Eleven men exercised in normobaric hypoxia for 90 minutes at 50% hypoxic VO2max.
Participants received either carbohydrate or placebo beverages after breakfast or without breakfast, enriched with U-13C6 D-glucose.
Indirect calorimetry and isotope ratio mass spectrometry calculated carbohydrate and fat oxidation.
No significant difference in relative substrate oxidation was observed in the first 60 minutes of exercise between carbohydrate and placebo trials.
Carbohydrate supplementation increased relative carbohydrate oxidation during exercise (>60 minutes) after breakfast omission, but not consumption. A reduction in relative liver glucose oxidation was noted in the carbohydrate trials.
PRACTICAL TAKEAWAY
The results of this study suggest that carbohydrate supplementation during prolonged exercise in hypoxia may enhance carbohydrate oxidation, especially when undertaken without prior breakfast consumption. Appetite may be suppressed at altitude so it is useful to consider strategies such as this for athletes exercising at altitude. My recommendation is for athletes to fuel all of their training at altitude (even easy sessions) to ensure that they achieve the most benefit from their time at altitude.
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 (365 studies and practical takeaways). Last week, the newsletter covered studies on the following topics:
Carbohydrate dose for performance during prolonged exercise
Training at higher percentages of VO2 Max induces greater adaptions
Subcellular muscle glycogen utilisation during exercise
Considerations for ultra-endurance activities
Pre-sleep casein protein ingestion does not impact next-day appetite