RESEARCH: Studies reviewed this week: 14 December 2020 to 20 December 2020

TRAINING: Muscle hypertrophy and muscle strength: dependent or independent variables?

An important question for athletes who need to manage their weight is whether or not increased strength also means additional muscle size. This review analysed studies "that have monitored in parallel changes in muscle size and changes in muscle force, measured in isometric contractions in vivo, in isolated muscles ex vivo (in rodents) and in single muscle fibers".

The authors found that:

Although a general positive relation exists among the two variables, a number of studies show a clear dissociation with increase of muscle size with no change or even decrease in strength and, vice versa, increase in strength without increase in size.

PRACTICAL TAKE AWAY - it is possible to increase strength without muscle size increases.

EQUIPMENT: Enhanced Cycling Time-Trial Performance During Multiday Exercise With Higher-Pressure Compression Garment Wear

I've shared a study in the past about compression clothing reducing intestinal damage in marathon runners (which still seems strange to me...). This study "tested the hypothesis that increased pressure levels applied via high-pressure compression garments would enhance multiday exercise performance". This is useful to think about because compression has been shown to be useful in recovery, but not necessarily in performance tests.

The authors tested a control (CON), low-compression clothing (LC), and high-compression clothing (HC) over a series of time trials:

An initial high-intensity protocol, a 24-hour period of controlled rest while wearing the applied condition/garment (CON, LC, and HC), and a subsequent 8-km cycling time trial, while wearing the respective garment.

The outcomes proved very favorable for the high-compression group:

Time-trial performance was significantly improved during HC compared with both CON and LC. In addition, plasma lactate was significantly lower at 30 and 60 minutes postexercise on day 1 in HC compared with CON.

PRACTICAL TAKE AWAY - compression clothing that offers a high level of compression and when used in multiple performance trials with limited recovery may enhance performance.

HEAT & ALTITUDE: Concurrent Heat and Intermittent Hypoxic Training: No Additional Performance Benefit Over Temperate Training

I have shared multiple different studies on both heat and altitude interventions (easiest to see them all on the resources page). However, it's an important consideration to think about whether these two types of training interventions are additive. This study set out to "examine whether concurrent heat and intermittent hypoxic training can improve endurance performance and physiological responses relative to independent heat or temperate interval training".

The authors tested there different 3-week training protocols: heat intervention, control, and heat and hypoxia. The results showed that:

There was improved 20-km TT performance to a similar extent across all groups. Plasma volume and blood volume were both increased at mid in HOT and H+H over CONT. Increased hemoglobin mass was observed in H+H only

PRACTICAL TAKE AWAY - there does not appear to be any added benefit from combining heat and altitude that cannot be achieved by using just one of these interventions. Consider the demands of your race to guide your training camp, and if there are no particular heat or altitude race demands, choose one or the other depending on whichever suits you better.

TRAINING: Exercise for Weight Loss: Further Evaluating Energy Compensation with Exercise

In this study the authors set out to test whether more frequent exercise, and therefore a greater energy deficit, would result in larger compensatory behaviour than less frequent exercise. The implications being that automatic compensatory responses may reduce the benefit of increased exercise frequency. They found that:

The primary finding that energy compensation is not influenced by exercise dose, rather, greater energy expenditures (approaching 3000 kcal·wk−1) are needed to overcome this compensatory response to produce significant reductions in body fat.

PRACTICAL TAKE AWAY - if you are trying to lose weight, achieving a minimal threshold of ~3000kcal/week of exercise-induced enery expenditure may be needed to start seeing fat loss benefits.

TRAINING: Effects of Resistance Training on Muscle Size and Strength in Very Elderly Adults

In this review the authors investigated studies to understand whether resistance training can benefit very old athletes (75 years old and older). The key findings were:

  • The meta-analysis found a significant effect of resistance training on muscle strength in the very elderly.
  • In a subgroup analysis that included only the oldest-old participants (80 + years of age), there was a significant effect of resistance training on muscle strength.
  • For whole-muscle hypertrophy, there was a significant effect of resistance training in the very elderly.
  • There were minimal reports of adverse events associated with the training programs in the included studies.

PRACTICAL TAKE AWAY - elderly athletes can increase strength through resistance training. Keep up your strength training programmes!

RECOVERY: Prolonging the duration of cooling does not enhance recovery following a marathon

Runners have used cryotherapy to try and improve recovery after their training. This study set out "to test the efficacy of prolonging the duration of cooling using [phase cahnge material packs] PCM on perceptual recovery, neuromuscular function, and blood markers following a marathon run". The protocol involved thirty participants who completed a marathon run and were randomized to receive three hours of 15°C PCM treatment covering the quadriceps or recover without an intervention (control).

The authors found that:

The marathon led to decreases in muscle function, increases in perceptions of soreness, and increases in blood markers of muscle damage (CK) and inflammation (hsCRP). Contrary to the hypothesis, and unlike our previous work,26-29 there was no difference in the rate of recovery between the PCM treatment and control groups.
These results indicate that prolonged PCM cooling was not an effective recovery strategy when administered after running a marathon.

PRACTICAL TAKE AWAY - cryotherapy and longer periods of cooling do not appear to enhance recovery after a marathon.

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