RESEARCH: studies reviewed this month - January 2020

PHYSIOLOGY: Regular changes in foot strike pattern during prolonged downhill running do not influence neuromuscular, energetics, or biomechanical parameters

This study set out to investigate the claim that "that a high variability in foot strike pattern during downhill running is associated with lower neuromuscular fatigue of the plantar flexors". The idea is that by deliberately changing foot strike patterns the runner uses different muscles and can reduce their overall fatigue. Through a methodology that included 2.5hr graded running tests, the study found that:

A deliberate strategy to alternate between foot strike patterns did not reduce the extent of fatigue during prolonged graded running.
It is not the ability to switch between foot strike patterns that minimises fatigue; rather the ability to adapt foot strike pattern to the terrain and therefore a better running technique.

PRACTICAL TAKE AWAY - don't try to adjust your foot strike to reduce fatigue rather incorporate varied terrain in your training to encourage natural adaptation of foot strike.

RECOVERY: The relationship between objective measures of sleep and training load across different phases of the season in American collegiate football players

The sleep patterns of athletes are important components of their development and recovery. Most athletes know the importance of sleep, but the actual habits and other lifestyle factors can have an impact on the actual sleep athletes achieve. This study investigated the relationship between objective measures of sleep and training load across different phases of the American collegiate football season.

The concerning results showed that athletes achieved the least sleep when they needed it most:

Overall, total sleep time was very likely shorter in Camp, almost certainly shorter In-Season and likely shorter in School compared to the Off-season phase.

PRACTICAL TAKE AWAY - knowing that sleep is important and achieving it are two different things. It is important to find ways to manage other life stress and ensure that it does not encroach on your ability to sleep.

ALTITUDE: High-Altitude Acclimatization Improves Recovery from Muscle Fatigue

This study looked at "the effect of high-altitude acclimatization on peripheral fatigue compared with sea level and acute hypoxia". This study is interesting because it is a different effect to the normal reason for going to altitude (to increase red blood cell count and adapt to lower O2 levels). The results found that there was a muscular adaptation to altitude:

Muscle adaptations occurring with chronic hypoxia, independent of other adaptations, positively influence muscle contractility during and after repeated contractions at high altitude.

PRACTICAL TAKE AWAY - there are additional benefits to training camps at altitude that include the ability to recovery from muscle fatigue. Altitude training camps may be useful for multiple factors beyond the standard expected adaptations.

NUTRITION: A Short-Term Ketogenic Diet Impairs Markers of Bone Health in Response to Exercise

Diet and especially low-carb approaches to diet are highly debated topics. This study looked into the a ketogenic diet and its impact on bone health with the goal to investigate:

diet-exercise interactions related to bone markers in elite endurance athletes after a 3.5-week ketogenic low-carbohydrate, high-fat (LCHF) diet and subsequent restoration of carbohydrate (CHO) feeding.

The findings suggest that a large intervention like starting a ketogenic diet may have negative effects on bone health:

Markers of bone modeling/remodeling were impaired after short-term LCHF diet, and only a marker of resorption recovered after acute CHO restoration. Long-term studies of the effects of LCHF on bone health are warranted.

PRACTICAL TAKE AWAY - be very careful when adopting a diet intervention and be aware that there may be unexpected consequences on other aspects of health. In particular, the ketogenic diet may impact bone health.

NUTRITION: Pre-Sleep Casein Protein Ingestion Does Not Impact Next-Day Appetite, Energy Intake and Metabolism in Older Individuals

I have taken a protein supplement before bed (usually casein protein) when in heavy training blocks so I was wondering if this affected my appetite the next morning. The only study I could find was on older individuals, but it was looking at the exact questions I wanted the answer to: " the purpose of the current study was to investigate the effects of a pre-sleep protein drink on next-morning appetite, energy intake and metabolism". The results suggest that there is no impact on next day nutrition:

No between-group differences were observed for appetite and energy intake at breakfast. Furthermore, RMR, RER, and assessed blood markers were not significantly different between any of the treatment groups. Pre-sleep protein intake does not affect next-morning appetite and energy intake and is therefore a viable strategy to increase daily protein intake.

PRACTICAL TAKE AWAY - additional protein intake before bed will not impact next-day appetite or reduce protein intake therefore it is a useful way to increase daily protein intake.

NUTRITION: Vitamin D and Calcium for the Prevention of Fracture

This study set out to answer the question: "what is the available evidence for the efficacy of vitamin D with or without calcium supplementation for reducing the risk of fracture?". This was a systemic review of previous randomized clinical trials. The key finding of the review were that:

neither intermittent nor daily dosing with standard doses of vitamin D alone was associated with reduced risk of fracture, but daily supplementation with both vitamin D and calcium was a more promising strategy.

PRACTICAL TAKE AWAY - if supplementing for bone health it is beneficial to take both Vitamin D and Calcium together. The most common dose in the studies was 800 or 400 IU of vitamin D per day and 1200 or 800 mg of calcium per day.

TRAINING: Effects of Strength Training on Running Economy in Highly Trained Runners: A Systematic Review With Meta-Analysis of Controlled Trials.

The goal of this study was to review previous studies "to determine the effect of strength training programs on the running economy (RE) of high-level middle- and long-distance runners". The review found strong evidence to show that:

a strength training program including low to high intensity resistance exercises and plyometric exercises performed 2-3 times per week for 8-12 weeks is an appropriate strategy to improve RE in highly trained middle- and long-distance runners.

PRACTICAL TAKE AWAY - keep doing strength training to improve running economy!

PHYSIOLOGY: Effect of limb mass and its distribution on the energetic cost of running

This study looked at the weight of limbs and the cost of running. To do this the researchers "measured changes in the rate of energy consumption of running human subjects produced by artificial alterations in limb inertial properties", finding that:

The cost of adding a given mass to the limbs is significantly greater than adding it to the centre of mass and that this effect becomes more pronounced as the limb loads are moved distally.
Thus a clear effect of limb mass and its distribution on cost of locomotion has been demonstrated.

PRACTICAL TAKE AWAY - while it is not possible to change the mass of the limb, it is possible to change the weight of shoes and socks worn (and any other limb covering). In terms of cost of running reducing this weight to the minimum possible will decrease running cost.

No comments: