RESEARCH: Studies reviewed this week: 22 November 2021 to 28 November 2021

ALTITUDE: Effects of graded hypoxia during exhaustive intermittent cycling on subsequent exercise performance and neuromuscular responses

This study set out to determine "the effect of graded hypoxia during exhaustive intermittent cycling on subsequent exercise performance and neuromuscular fatigue characteristics in normoxia". Cyclists performed two different exhaustive intermittent tests 30' apart with the first one performed in either sea level, moderate hypoxia, or severe hypoxia conditions.

The authors found that:

The number of efforts completed decreased with increasing hypoxic severity during exhaustive intermittent cycling exercise (EICE) 1, whereas there was no difference between conditions during EICE 2.
There were no significant difference in any neuromuscular parameters from post-EICE 1 to post-EICE 2.
Increasing hypoxia severity during exhaustive intermittent cycling hampered exercise capacity, but did not influence performance and associated neuromuscular responses during a subsequent bout of exercise in normoxia performed after 30 min of rest.

PRACTICAL TAKEAWAY - if you are able to perform training in hypoxia, this does not appear to have a negative impact on subsequent sessions. This has implications for planning and implementing these types of sessions.

NUTRITION: Nitrate-rich beetroot juice ingestion reduces skeletal muscle O2 uptake and blood flow during exercise in sedentary men

This study set out to investigate "the effects of nitrate supplementation on local metabolic and haemodynamic regulation in contracting human skeletal muscle". The authors explain that nitrate supplementation has been shown to reduce pulmonary O2 uptake during submaximal exercise and enhance exercise performance, but that the effect in the muscle is unclear. They found that:

Compared with PLA, NO3 increased plasma levels of nitrate and nitrite. During MOD, leg VO2 and leg blood flow (LBF) were reduced to a similar extent in NO3.
In NO3, a reduction in nitrate and nitrite concentration was detected between arterial and venous samples.


No difference in the time to exhaustion was observed between conditions.

PRACTICAL TAKEAWAY - while nitrate-rich beetroot juice has shown to be beneficial for exercise performance, it does not appear to be performance enhancing at the muscular level.

NUTRITION: Modulation of Exercise-Induced Muscle Damage, Inflammation, and Oxidative Markers by Curcumin Supplementation in a Physically Active Population

This critical review set out to "evaluate the effectiveness of curcumin supplementation on exercise-induced muscle damage (EIMD) and inflammatory and oxidative markers in a physically active population" with the view that this could help reduce EIMD and therefore improve performance.

The researchers found that the use of curcumin:

  • reduces the subjective perception of the intensity of muscle pain
  • reduces muscle damage through the decrease of creatine kinase (CK)
  • increases muscle performance
  • has an anti-inflammatory effect by modulating the pro-inflammatory cytokines, such as TNF-α, IL-6, and IL-8
  • may have a slight antioxidant effect

This led them to conclude that:

The administration of curcumin at a dose between 150–1500 mg/day before and during exercise, and up until 72 h’ post-exercise, improved performance by reducing EIMD and modulating the inflammation caused by physical activity.

PRACTICAL TAKEAWAY - curcumin supplementation could be beneficial for performance and recovery.

NUTRITION: Energy deficiency impairs resistance training gains in lean mass but not strength

In this meta review the authors explored "the effects of prolonged energy deficits on resistance training (RT) outcomes". They explain that short-term energy deficits are know to impair anabolic hormones and protein synthesis and sought to understand what happens in studies that were longer than 3 weeks in duration.

The two practical takeaways from the review were:

Individuals performing RT to build lean muscle (LM) should avoid prolonged energy deficiency.
Individuals performing RT to preserve LM during weight loss should avoid energy deficits >500 kcal/day.

PRACTICAL TAKEAWAY - prolonged energy deficiencies will impair lean mass growth and should be carefully avoided.

PHYSIOLOGY: Evidence of region-specific right ventricular functional adaptation in endurance-trained men in response to an acute volume infusion

In this study the authors examined "the impact of acute blood volume expansion on right ventricle (RV) wall mechanics'. This provides a useful insight into the changes in the heart as a result of endurance training.

The study concludes:

Endurance training results in a greater contribution to longtitudinal myocardial deformation at the base of the RV in response to haemodynamic volume challenge, which might reflect a greater region-specific functional reserve capacity.

PRACTICAL TAKEAWAY - the heart adapts to endurace training by increasing the RV functional reserve capacity.

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