RESEARCH: Studies reviewed this week: 2 November 2020 to 8 November 2020

TRAINING: Reduced training frequencies and maintenance of increased aerobic power

This study set out to understand how much training is required to maintain VO2Max. After a period of 10 weeks of training for 40' six days a week, the group was split into participants who only did two days a week and a group that only training four days a week for a further 15 weeks. The authors found that:

  • VO2max in the 4 d/wk and 2 d/wk groups remained essentially the same as the trained levels when determined at 5-wk intervals of reduced training.
  • More exercise is required to increase VO2max, than that required to maintain it at the trained level in young adults performing high-intensity exercise.

PRACTICAL TAKE AWAY - it requires less training to maintain VO2Max than to build it. This is useful knowledge that can be applied during off-season periods and also when during block periodisation training where other attributes are the focus.

TRAINING: Trunk and Upper Body Fatigue Adversely Affect Running Economy

Running economy is very important for runners at all distances. It is also something that is trainable. And, I believe that small gains in economy can help significantly when these are applied over the long duration of ultramarathons. This study investigated the impacts of trunk and upper body fatigue on running economy.

These conditions may be particularly relevant to trail runners who carry packs and who use poles as it is possible these additional factors may produce more fatigue in the truck and upper body. The authors found that:

RE differed, although not significantly, between control and both fatigue protocols by 0.75 to 1.5 ml/min/kg bodyweight with a moderate to large effect size. Despite no statistical signficance, the largest RE differences were observed between trunk fatigue and control (and underscored by the moderate to large effect size).

While this is a preliminary study and it found no statistical differences between conditions, there were some effects and this prompted the authors to suggest that more work is required in this area. They suspect that there may be some potential that "periodized core training can beneficially preserve RE".

PRACTICAL TAKE AWAY - although this study was not definite proof of the value of core strength and reduced fatigue on running economy, it does seem to be a hypothesis worth exploring further in your own training. I would suggest maintaining a core strength routine anyway.

NUTRITION: Fructose-Glucose Composite Carbohydrates and Endurance Performance

This literature review investigated the various papers that have been published on fructose-glucose CHO impacts on endurance performance. The authors identified the following key points:

  • Relative to isocaloric glucose/maltodextrin, the ingestion of 0.5-1.0:1-ratio fructose:glucose/maltodextrin beverages at 1.3-2.4 g carbohydrate/min produced small to moderate enhancements in mean power.
  • When 0.5:1-ratio composites were ingested at ≥1.7 g/min, improvements were larger than at 1.4-1.6 g/min.
  • Solutions containing a 0.7-1.0:1 fructose:glucose ratio were absorbed fastest; when ingested at 1.5-1.8 g/min, a 0.8:1 fructose:glucose ratio conveyed the highest exogenous carbohydrate energy and endurance power compared with lower or higher fructose:glucose ratios.
  • To conclude, ingesting 0.5-1.0:1-ratio fructose:glucose/maltodextrin beverages at 1.3-2.4 g/min likely benefits 2.5-3.0 h endurance power versus isocaloric single saccharide.

PRACTICAL TAKE AWAY - CHO ingestion at 78-144g/hr using a blend of fructose:glucose/maltodextrin is optimal for performance benefits.

NUTRITION: The Effects of Caffeine Mouth Rinsing on Exercise Performance: A Systematic Review

There is some good research on using CHO mouth rinses to improve performance either at the end of endurance events or when an athlete is struggling to ingest food. This literature review looked at the same concept for caffeine with the goal to help athletes who experience negative impacts of ingesting caffeine. The process was described by the authors as "Mouth rinse protocols involve swilling a solution within the oral cavity for a short time (e.g., 5–10 s) before expectorating it to avoid systemic absorption". The authors found:

Three studies found significant positive effects of caffeine mouth rinsing on exercise performance, whereas the remaining eight found no improvements or only suggestive benefits.

The mixed results may be due to heterogeneity in the methods across studies, interindividual differences in bitter tasting, and differences in the concentrations of caffeine solutions.

PRACTICAL TAKE AWAY - at this point in time it doesn't not appear that a caffeine mouth rinse is effective.

TRAINING: Predefined vs data‐guided training prescription based on autonomic nervous system variation

This systematic review compared "physiological adaptations and/or improvements in performance following training based on responses of the autonomic nervous system (ie, changes in heart rate variability) and predefined training". The authors used studies that met the following characteristics:

  • involved interventions consisting predominantly of running training;
  • lasted at least 3 weeks;
  • reported pre‐ and post‐intervention assessment of running performance and/or physiological parameters;
  • included an experimental group performing training adjusted continuously on the basis of alterations in HRV and a control group; and
  • involved healthy runners.

The key findings were:

  • In five interventions, improvements in performance parameters (3000m, 5000m, Loadmax, Tlim) were more pronounced following HRV‐based training.
  • Peak oxygen uptake and submaximal running parameters (eg, LT1, LT2) improved following both HRV‐based and predefined training, with no clear difference in the extent of improvement in VO2Max peak.
  • Submaximal running parameters tended to improve more following HRV‐based training.

PRACTICAL TAKE AWAY - all the training prescriptions produced performance benefits, with HRV-based training showing good signs in some studies and with certain aspects of training. HRV-based training is worth considering and trying in your programme.

TRAINING: The Time-Course of Changes in Muscle Mass, Architecture and Power During 6 Weeks of Plyometric Training

I've shared a few studies about the benefits of plyometrics in the past (plyometrics for ultramarathons, complex strength training for marathon runners, explosive strength training for 5km runners, depth jumps). This study investigated the effects of 6 weeks of 3 times per week plyometric training. The authors found:

Plyometrics training induced rapid increases in muscle volume, fascicle length, pennation angle, torque and power in healthy younger adults.

PRACTICAL TAKE AWAY - plyometrics work. Do your plyometrics!

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