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Friday, March 28, 2014

Effect of cryotherapy on performance: what's new?

Open Access J Sports Med. 2014 Mar 10;5:25-36. eCollection 2014.

Whole-body cryotherapy: empirical evidence and theoretical perspectives. Bleakley CM, Bieuzen F, Davison GW, Costello JT.

Abstract
Whole-body cryotherapy (WBC) involves short exposures to air temperatures below -100°C. WBC is increasingly accessible to athletes, and is purported to enhance recovery after exercise and facilitate rehabilitation postinjury. Our objective was to review the efficacy and effectiveness of WBC using empirical evidence from controlled trials. We found ten relevant reports; the majority were based on small numbers of active athletes aged less than 35 years. Although WBC produces a large temperature gradient for tissue cooling, the relatively poor thermal conductivity of air prevents significant subcutaneous and core body cooling. There is weak evidence from controlled studies that WBC enhances antioxidant capacity and parasympathetic reactivation, and alters inflammatory pathways relevant to sports recovery. A series of small randomized studies found WBC offers improvements in subjective recovery and muscle soreness following metabolic or mechanical overload, but little benefit towards functional recovery. There is evidence from one study only that WBC may assist rehabilitation for adhesive capsulitis of the shoulder. There were no adverse events associated with WBC; however, studies did not seem to undertake active surveillance of predefined adverse events. Until further research is available, athletes should remain cognizant that less expensive modes of cryotherapy, such as local ice-pack application or cold-water immersion, offer comparable physiological and clinical effects to WBC.

FULL paper http://www.dovepress.com/whole-body-cryotherapy-empirical-evidence-and-theoretical-perspectives-peer-reviewed-article-OAJSM


Int J Sports Physiol Perform. 2013 May;8(3):227-42. Epub 2013 Feb 20.
Cooling and performance recovery of trained athletes: a meta-analytical review. Poppendieck W, Faude O, Wegmann M, Meyer T.

Abstract
PURPOSE: Cooling after exercise has been investigated as a method to improve recovery during intensive training or competition periods. As many studies have included untrained subjects, the transfer of those results to trained athletes is questionable. METHODS: Therefore, the authors conducted a literature search and located 21 peer-reviewed randomized controlled trials addressing the effects of cooling on performance recovery in trained athletes. RESULTS: For all studies, the effect of cooling on performance was determined and effect sizes (Hedges' g) were calculated. Regarding performance measurement, the largest average effect size was found for sprint performance (2.6%, g = 0.69), while for endurance parameters (2.6%, g = 0.19), jump (3.0%, g = 0.15), and strength (1.8%, g = 0.10), effect sizes were smaller. The effects were most pronounced when performance was evaluated 96 h after exercise (4.3%, g = 1.03). Regarding the exercise used to induce fatigue, effects after endurance training (2.4%, g = 0.35) were larger than after strength-based exercise (2.4%, g = 0.11). Cold-water immersion (2.9%, g = 0.34) and cryogenic chambers (3.8%, g = 0.25) seem to be more beneficial with respect to performance than cooling packs (-1.4%, g= -0.07). For cold-water application, whole-body immersion (5.1%, g = 0.62) was significantly more effective than immersing only the legs or arms (1.1%, g = 0.10). CONCLUSIONS: In summary, the average effects of cooling on recovery of trained athletes were rather small (2.4%, g = 0.28). However, under appropriate conditions (whole-body cooling, recovery from sprint exercise), postexercise cooling seems to have positive effects that are large enough to be relevant for competitive athletes.


J Strength Cond Res. 2014 Mar 11. [Epub ahead of print]
Effect of run training and cold-water immersion on subsequent cycle training quality in high performance triathletes. Rowsell GJ, Reaburn P, Toone R, Smith M, Coutts AJ.

Abstract
The purpose of the study was to investigate the effect of cold-water immersion (CWI) on physiological, psychological, and biochemical markers of recovery and subsequent cycling performance following intensive run training. Seven high-performance male triathletes (age: 28.6±7.1 y; cycling VO2peak: 73.4±10.2 mL·kg·min) completed two trials in a randomized crossover design consisting of 7 x 5-min running intervals at 105% of Individual Anaerobic Threshold followed by either CWI (10°C±0.5°C) or thermoneutral water immersion (TNI; 34±0.5°C). Subjects immersed their legs in water five times for 60-s with 60-s passive rest between each immersion. Nine hours post-immersion, inflammatory and muscle damage markers, and perceived recovery measures were obtained before the subjects completed a 5-min maximal cycling test followed by a high quality cycling interval training set (6 x 5-min intervals). Power output, heart rate (HR), blood lactate (La) and rating of perceived exertion (RPE) were also recorded during the cycling time-trial and interval set. Performance was enhanced (change, ±90% confidence limits) in the CWI condition during the cycling interval training set (power output (W·kg ), 2.1±1.7%, La (mmol·L), 18±18.1%, La:RPE, 19.8±17.5%). However, there was an unclear effect of CWI on 5-min maximal cycling time-trial performance and there was no significant influence on perceptual measures of fatigue/recovery, despite small to moderate effects. The effect of CWI on the biochemical markers was mostly unclear, however there was a substantial effect for interleukin-10 (20±13.4%). These results suggest that compared to TNI, CWI may be effective for enhancing cycling interval training performance following intensive interval running training.


J Sport Rehabil. 2014 Mar 12. [Epub ahead of print]
Comparison of Electrical Stimulation Versus Cold Water Immersion Treatment on Muscle Soreness Following Resistance Exercise. Jajtner AR, Hoffman JR, Gonzalez AM, Worts P, Fragala MS, Stout JR.

Abstract
CONTEXT: Resistance training is a common form of exercise for competitive and recreational athletes. Enhancing recovery from resistance training may potentially improve the muscle remodeling processes, stimulating a faster return to peak performance. OBJECTIVE: To examine the effects of two different recovery modalities, neuromuscular electrical stimulation (NMES), and cold water immersion (CWI) on performance, biochemical and ultrasonographic measures. PARTICIPANTS: Thirty resistance-trained males (23.1±2.9yrs; 175.2±7.1cm; 82.1±8.4kg) were randomly assigned to NMES, CWI or control (CON). DESIGN AND SETTING: All participants completed a high-volume lower-body resistance training workout on day one and returned to the Human Performance Lab 24- (24H) and 48h (48H) post-exercise for follow-up testing. MEASURES: Blood samples were obtained pre-exercise (PRE), immediately post (IP), 30-minutes post (30P), 24H and 48H. Subjects were examined for performance changes in the squat exercise (total repetitions, and average power per repetition), biomarkers of inflammation, and changes in cross sectional area (CSA) and echo intensity (EI) of the rectus femoris (RF) and vastus lateralis (VL) muscles. RESULTS: No differences between groups were observed in the number of repetitions (p=0.250; power: p=0.663). Inferential based analysis indicated that increases in C-reactive protein (CRP), concentrations were likely increased by a greater magnitude following CWI compared to CON, while NMES possibly decreased more than CON from IP to 24H. Increases in IL-10 concentrations between IP-30P were likely greater in CWI than NMES, but not different compared to CON. Inferential based analysis of RF EI indicated a likely decrease for CWI between IP-48H. No other differences between groups were noted in any other muscle architecture measures. CONCLUSIONS: Results indicated that CWI induced greater increases in pro- and anti-inflammatory markers, while decreasing RF EI, suggesting CWI may be effective in enhancing short-term muscle recovery following high-volume bouts of resistance exercise.

Friday, March 14, 2014

Carbohydrate ingestion during exercise: time to rethink its role?

The effect of carbohydrate (CHO) ingestion on performance during prolonged exercise has been investigated in a number of studies. The majority of published papers show a positive effect. Does this fact mean that CHO ingestion during exercise is beneficial to exercise performance under all conditions? Is this effect due to biological advantage? 

Nassif and colleagues from the School of Human Movement Studies, Charles Sturt University, Australia, published a nice study in 2008 that questions the value of CHO ingestion during exercise.

What they did?
Nine well trained athletes with VO2max 65.8 ml/kg/min cycled at 70% of VO2max until volitional fatigue under three experimental conditions while
  • ingesting placebo capsules with distillated water (PLAc),
  • ingesting CHO capsules with distillated water (CHOc),
  • ingesting CHO capsules with distillated water whilst both researchers and athletes knew that CHO were being consumed (CHOk).

What they found?
  • Exercise duration was similar between PLAc and CHOc
  • Exercise duration was 24% longer in CHOk compared with PLAc

Take-home message
  • The ingestion of carbohydrate capsules did not improve performance under these experimental conditions.
  • Knowledge of the ingested ergogenic substance may improve performance. "Coaches and trainers of endurance athletes should be aware that knowledge of the performance enhancement supplement may have a significant psychological effect on endurance performance" (Nassif et al., 2008). 

Source
Nassif et al. Double blind carbohydrate ingestion does not improve exercise duration in warm humid conditions. Journal of Science and Medicine in Sport 2008; 11: 72-79.

Friday, March 7, 2014

Repeated sprint training in hypoxia: a new training method?



scienceopen.com
 The use of methods to speed up adaptations to training are of major importance especially for high level athletes. Along this line, recent studies have investigated the repeated sprint training in hypoxia as a new training method. Raphael Faiss, Olivier Girard and Gregoire Millet from Aspetar and the University of Lausanne have published a relevant review in the December issue of the British Journal of Sports Medicine which is free to download at http://bjsm.bmj.com/content/47/Suppl_1/i45.full.pdf+html

Given the opportunity you can also watch the video of a recent study conducted by Olivier in Aspetar (http://www.youtube.com/watch?v=cl62P771uU4 ).

Hope you enjoy both!

George


How to make millionaires to sweat?

huffingtonpost.com
This is one of the most challenging opportunities in our professional life. Are millionaires willing to sweat and improve themselves? How can we (the sport scientists) influence them to work harder? Here are some tips:

  • Share with them your vision and plans: show them that you are ready to sweat first. If they see the “fire inside” you they will follow.
  • Ask them to set their objectives: Simply, they must write on a piece of paper how they see themselves next year, after 2 years etc. Ask them to write down the objective of each month. The objectives must be SMART (Specific-Measurable-Achievable-Relevant-Time based).
  • Give them feedback: Have they achieved this month’s objective? Why not? What they have to change? Be honest and specific. 
  • Challenge them: Millionaires need new approaches, methods and more challenging targets. Stress yourself to find new ideas. Get out of your comfort zone. Challenge them to get out of their comfort zone!

Saturday, March 1, 2014

Does wearing compression garments improve performance and speed-up recovery?

Del Coso et al. Compression stockings do not improve muscular performance during a half-ironman triathlon race. Eur J Appl Physiol. 2014, 114(3):587-95.

Abstract
PURPOSE: This study aimed at investigating the effectiveness of compression stockings to prevent muscular damage and preserve muscular performance during a half-ironman triathlon.

METHODS: Thirty-six experienced triathletes volunteered for this study. Participants were matched for age, anthropometric data and training status and placed into the experimental group (N = 19; using ankle-to-knee graduated compression stockings) or control group (N = 17; using regular socks). Participants competed in a half-ironman triathlon celebrated at 29 ± 3 °C and 73 ± 8 % of relative humidity. Race time was measured by means of chip timing. Pre- and post-race, maximal height and leg muscle power were measured during a countermovement jump. At the same time, blood myoglobin and creatine kinase concentrations were determined and the triathletes were asked for perceived exertion and muscle soreness using validated scales.

RESULTS: Total race time was not different between groups (315 ± 45 for the control group and 310 ± 32 min for the experimental group; P = 0.46). After the race, jump height (-8.5 ± 3.0 versus -9.2 ± 5.3 %; P = 0.47) and leg muscle power reductions (-13 ± 10 versus -15 ± 10 %; P = 0.72) were similar between groups. Post-race myoglobin and creatine kinase concentrations were not different between groups. Perceived muscle soreness (5.3 ± 2.1 versus 6.0 ± 2.0 arbitrary units; P = 0.42) and the rating of perceived effort (17 ± 2 versus 17 ± 2 arbitrary units; P = 0.58) were not different between groups after the race.

CONCLUSION: Wearing compression stockings did not represent any advantage for maintaining muscle function or reducing blood markers of muscle damage during a triathlon event.



Vercruyssen et al. The influence of wearing compression stockings on performance indicators and physiological responses following a prolonged trail running exercise. Eur J Sport Sci. 2014,14(2):144-50.

Abstract
The objective of this study was to investigate the effects of wearing compression socks (CS) on performance indicators and physiological responses during prolonged trail running. Eleven trained runners completed a 15.6 km trail run at a competition intensity whilst wearing or not wearing CS. Counter movement jump, maximal voluntary contraction and the oxygenation profile of vastus lateralis muscle using near-infrared spectroscopy (NIRS) method were measured before and following exercise. Run time, heart rate (HR), blood lactate concentration and ratings of perceived exertion were evaluated during the CS and non-CS sessions. No significant difference in any dependent variables was observed during the run sessions. Run times were 5681.1±503.5 and 5696.7±530.7 s for the non-CS and CS conditions, respectively. The relative intensity during CS and non-CS runs corresponded to a range of 90.5-91.5% HRmax.

Although NIRS measurements such as muscle oxygen uptake and muscle blood flow significantly increased following exercise (+57.7% and + 42.6%,+59.2% and + 32.4%, respectively for the CS and non-CS sessions, P<0.05), there was no difference between the run conditions.

The findings suggest that competitive runners do not gain any practical or physiological benefits from wearing CS during prolonged off-road running.



Bieuzen et al. Effect of wearing compression stockings on recovery after mild exercise-induced muscle damage. Int J Sports Physiol Perform. 2014, 9(2):256-64. 

Abstract
Background: Compression garments are increasingly popular in long-distance running events where they are used to limit cumulative fatigue and symptoms associated with mild exercise-induced muscle damage (EIMD). However, the effective benefits remain unclear.

Objective: This study examined the effect of wearing compression stockings (CS) on EIMD indicators. Compression was applied during or after simulated trail races performed at competition pace in experienced off-road runners.

Methods: Eleven highly trained male runners participated in 3 simulated trail races (15.6 km: uphill section 6.6 km, average gradient 13%, and downhill section 9.0 km, average gradient -9%) in a randomized crossover trial. The effect of wearing CS while running or during recovery was tested and compared with a control condition (ie, run and recovery without CS; non-CS). Indicators of muscle function, muscle damage (creatine kinase; CK), inflammation (interleukin-6; IL-6), and perceived muscle soreness were recorded at baseline (1 h before warm-up) and 1, 24, and 48 h after the run.

Results: Perceived muscle soreness was likely to be lower when participants wore CS during trail running compared with the control condition (1 h postrun, 82% chance; 24 h postrun, 80% chance). A likely or possibly beneficial effect of wearing CS during running was also found for isometric peak torque at 1 h postrun (70% chance) and 24 h postrun (60% chance) and throughout the recovery period on countermovement jump, compared with non-CS. Possible, trivial, or unclear differences were observed for CK and IL-6 between all conditions.

Conclusion: Wearing CS during simulated trail races mainly affects perceived leg soreness and muscle function. These benefits are visible very shortly after the start of the recovery period.

Source
PubMed