RESEARCH: studies I shared this week: 29 August 2022 to 4 September 2022

All of the studies I've shared (~500 studies) are available on the RESOURCES PAGE.

PHYSIOLOGY: The Effectiveness of Gait Retraining on Running Kinematics, Kinetics, Performance, Pain, and Injury in Distance Runners

PRACTICAL TAKEAWAYS -

1. Moderate-certainty evidence indicated step rate gait retraining increased step rate and reduced average vertical loading rate.
2. Low-certainty evidence indicated non-rearfoot footstrike retraining increased knee flexion at initial contact, but did not alter running economy.
3. Low-certainty evidence indicated multiparameter retraining did not alter running economy or performance
4. Gait retraining does not appear to improve performance.

CHO: The Ergogenic Effects of Acute Carbohydrate Feeding on Resistance Exercise Performance

PRACTICAL TAKEAWAYS -

1. Carbohydrate ingestion has an ergogenic effect on RT performance by enhancing volume performance, which is more likely to occur when sessions exceed 45 min and where the fast duration is ≥ 8 h.
2. The effect is moderated by the number of maximal effort sets completed, but not the load used or CHO dose.
3. CHO ingestion is beneficial for strength training.

CHO: What Is the Evidence That Dietary Macronutrient Composition Influences Exercise Performance?

PRACTICAL TAKEAWAYS -

1. There is little if any evidence that high-carbohydrate diets are essential for superior athletic performance.
2. These results identify hepatic glycogen as a key regulator of endurance capacity in mice, an effect that may be exerted through the maintenance of blood glucose levels.
3. In humans, quite small amounts of carbohydrate, ingested before or during exercise, are required to ensure that hypoglycemia does not develop during exercise. Ingesting more than that amount will not produce a superior outcome.
4. Prins et al. made the prediction that at least 88% of all the runners in the United States will not improve their 5 km running performances by following a high-carbohydrate diet.
5. It is now high time to move away from the universal prescription of high-carbohydrate diets for all athletes regardless of their levels of athletic performance or insulin resistance on the false grounds that only high-carbohydrate diets will maximize athletic performance in all.

DOWNHILL: Acute and delayed peripheral and central neuromuscular alterations induced by a short and intense downhill trail run

PRACTICAL TAKEAWAYS -

1. Our purpose was to investigate the consequences of an intense downhill trail run (DTR) on peripheral and central neuromuscular fatigue at knee extensors (KE) and plantar flexors (PF).
2. Decreased KE and PF voluntary activation (VA), evoked forces, VL M-wave amplitude, and KE low-frequency fatigue were observed at Post.
3. The acute KE VA deficit was about a third of that reported after ultramarathons, although peripheral alterations were similar.
4. The prolonged force loss seems to be mainly associated to VA deficit likely induced by the delayed inflammatory response to DTR-induced ultrastructural muscle damage.

DOWNHILL: Fatigue associated with prolonged graded running

PRACTICAL TAKEAWAYS -

1. Downhill running induces severe lower limb tissue damage, indirectly evidenced by massive increases in plasma creatine kinase/myoglobin concentration or inflammatory markers.
2. Low-frequency fatigue in downhill running is attributed to mechanical stress at the interface sarcoplasmic reticulum/T-tubule, while the inorganic phosphate accumulation probably plays a central role in intense uphill running.

PHYSIOLOGY: Biomechanics and Physiology of Uphill and Downhill Running

PRACTICAL TAKEAWAYS -

1. In uphill running (UR), lower limb muscles perform a higher net mechanical work compared to LR and DR to increase the body's potential energy.
2. In downhill running (DR), energy dissipation is generally prevalent compared to energy generation.
3. The effects of slope on biomechanics, muscle contraction patterns and physiological responses have important implications for injury prevention and success of athletes engaged in graded running competitions.