RESEARCH: studies I shared this week: 5 to 11 December 2022

All of the studies I've shared (~600 studies) are available on the RESOURCES PAGE.

EQUIPMENT: Design feature combinations effects of running shoe on plantar pressure during heel landing: A finite element analysis with Taguchi optimization approach

STUDY DETAILS -

1. Reducing plantar pressure can be conducive to reducing running injury and improving running performance and is primarily achieved by modifying the design parameters of running shoes.
2. This study examines the effect of design parameters of running shoes (i.e., heel-cup, insole material, midsole material, and insole thickness) on landing peak plantar pressure and determines the combination of different parameters that optimize cushion effects by employing the Taguchi method.
3. In the descending order of percentage contribution was a conforming heel-cup (53.18%), insole material (25.89%), midsole material (7.81%), and insole thickness (2.69%).
4. The optimal design of running shoe in this study was achieved with a latex insole, a 6 mm insole thickness, an Asker C-45 hardness midsole, and a 100% conforming heel-cup.
5. The implementation of a custom conforming heel-cup is imperative for relieving high plantar pressure for long-distance heel-strike runners.

PRACTICAL TAKEAWAY - if you're having trouble with plantar pain while running, consider first using custom heel cups and then the insole material.

TAPER: Longer Disciplined Tapers Improve Marathon Performance for Recreational Runners

STUDY DETAILS -

1. The aim of this study was to analyse the taper strategies of recreational runners to determine whether particular forms of taper were more or less favorable to race-day performance.
2. We identified different types of taper based on a combination of duration (1–4 weeks of decreasing training) and discipline (strict tapers progressively decrease training in the weeks before the marathon, relaxed tapers do not).
3. Strict tapers were associated with better marathon performance than relaxed tapers and that longer tapers of up to 3 weeks were associated with better performance than shorter tapers.
4. Results indicated that strict 3-week tapers were associated with superior marathon finish-time benefits (a median finish-time saving of 5 min 32.4 s or 2.6%) compared with a minimal taper.
5. The findings also highlight how most recreational runners (64%) adopt less disciplined (2-week and 3-week) tapers and suggest that shifting to a more disciplined taper strategy could improve performance relative to the benefits of a less disciplined taper.

PRACTICAL TAKEAWAY - before a goal race, make sure that you have a detailed taper plan. Longer, 3 weeks, is probably better than shorter, and make sure to be disciplined in your taper to optimize race day performance.

PHYSIOLOGY: Acute Effects of Warming Up on Achilles Tendon Blood Flow and Stiffness

STUDY DETAILS -

1. The aim of this study was to investigate the acute effect of frequently used warm-up exercises on the Achilles tendon blood flow and stiffness.
2. Achilles tendon blood flow and stiffness measurements of 40 healthy subjects (20 men and 20 women) aged between 18 and 25 years were obtained before and immediately after 4 different warm-up exercises: running, plyometrics, eccentric heel drops, and static stretching.
3. The results of this study showed a significant increase in Achilles tendon blood flow and stiffness after 10 minutes of running and plyometrics.
4. Static stretching and eccentric exercises elicited no significant changes.
5. We advise the incorporation of highly intensive exercises such as running and plyometrics within warm-up programs.

PRACTICAL TAKEAWAY - if you are concerned about achilles issues, then including a warm-up of progressive running and plyometrics is the best way to increase blood flow before training.

HEAT: Ice slurry ingestion improves physical performance during high-intensity intermittent exercise in a hot environment

STUDY DETAILS -

1. We investigated the effects of the intake of low amounts of ice slurry at −2˚C on the tympanic temperature and exercise performance during repeated high-intensity intermittent exercises in a hot environment.
2. The participants ingested 450 g of −2˚C-ice slurry (ICE), or a 30˚Cbeverage (CON) having the same composition as ICE, or 30˚C-water (WAT) during the halftime break.
3. The tympanic temperature at the half-time break and beginning of the 2nd session was significantly lower in the ICE group as compared with the CON and WAT groups.
4. While the peak power and mean power during the 2nd session were significantly greater in the ICE group as compared with the CON and WAT groups.
5. These results suggest that intake of low-temperature ice slurry as a strategy for internal body cooling is useful for improving endurance exercise performance in hot environments.

PRACTICAL TAKEAWAY - ice slurries (even relative small ones of just one bottle) are beneficial for performance in the heat.

CAFFEINE: Effect of Pre-Exercise Caffeine Intake on Endurance Performance and Core Temperature Regulation During Exercise in the Heat

STUDY DETAILS -

1. To use a meta-analytical approach to determine the effect of pre-exercise caffeine intake on endurance performance (EP) and core temperature (CT) in the heat.
2. Respectively six and 12 studies examined caffeine’s impact on EP and CT, representing 52 and 205 endurance-trained individuals.
3. On average, 6 mg/kg body mass of caffeine were taken 1 h before exercises of ~ 70 min conducted at 34 °C and 47% relative humidity.
4. Caffeine supplementation non-significantly improved EP by 2.1 ± 0.8% and significantly increased the rate of change in CT by 0.10 ± 0.03 °C/h, compared with the ingestion of a placebo.
5. Caffeine ingestion of 6 mg/kg body mass ~ 1 h before exercise in the heat may provide a worthwhile improvement in EP, is unlikely to be deleterious to EP, and trivially increases the rate of change in CT.

PRACTICAL TAKEAWAY - caffeine is effective for performance improvement in hot conditions and does not see appear to have negative implications on core temperature.