Friday, April 24, 2015

Altitude & performance: what's new?

 2015 Feb 9. [Epub ahead of print]

"Live High-Train Low and High" Hypoxic Training Improves Team-Sport Performance.

Abstract

PURPOSE:

To investigate physical performance and hematological changes in 32 elite male team-sport players after 14 days of 'live high-train low' (LHTL) in normobaric hypoxia (≥14 h.day at 2800-3000 m) combined with repeated-sprint training (6 sessions of 4 sets of 5 x 5-s sprints with 25 s of passive recovery) either in normobaric hypoxia at 3000 m (LHTL+RSH, namely LHTLH; n = 11) or in normoxia (LHTL+RSN, namely LHTL; n = 12) compared to controlled 'live low-train low' (LLTL; n = 9).

METHODS:

Prior to (Pre-), immediately (Post-1) and 3 weeks (Post-2) after the intervention, hemoglobin mass (Hbmass) was measured in duplicate (optimized carbon monoxide rebreathing method) and vertical jump, repeated-sprint (8 x 20 m - 20 s recovery) and Yo-Yo Intermittent Recovery level 2 (YYIR2) performances were tested.

RESULTS:

Both hypoxic groups increased similarly Hbmass at Post-1 and Post-2 in reference to Pre- (LHTLH: +4.0%, P<0.001 and +2.7%, P<0.01; LHTL: +3.0% and +3.0%, both P<0.001), while no change occurred in LLTL. Compared to Pre-, YYIR2 performance increased by ∼21% at Post-1 (P<0.01) and by ∼45% at Post-2 (P<0.001) with no difference between the two intervention groups (vs. no change in LLTL). From Pre- to Post-1 cumulated sprint time decreased in LHTLH (-3.6%, P<0.001) and in LHTL (-1.9%, P<0.01), but not in LLTL (-0.7%), and remained significantly reduced at Post-2 (-3.5% P<0.001) in LHTLH only. Vertical jump performance did not change.

CONCLUSION:

'Live high-train low and high' hypoxic training interspersed with repeated sprints in hypoxia for 14 days (in-season) increases Hbmass, YYIR2 performance and repeated-sprint ability of elite field team-sport players with the benefits lasting for at least three weeks post-intervention.


 2015 Jan 26. [Epub ahead of print]

Altitude Training in Elite Swimmers for Sea Level Performance (Altitude Project).


INTRODUCTION:

This controlled nonrandomized parallel groups trial investigated the effects on performance, V˙o2 and hemoglobin mass (tHbmass) of 4 preparatory in-season training interventions: living and training at moderate altitude for 3 and 4 weeks (Hi-Hi3, Hi-Hi), living high and training high and low (Hi-HiLo, 4 weeks), and living and training at sea level (SL) (Lo-Lo, 4 weeks).

METHODS:

From 61 elite swimmers, 54 met all inclusion criteria and completed time trials over 50 and 400 m crawl (TT50, TT400), and 100 (sprinters) or 200 m (non-sprinters) at best stroke (TT100/TT200). V˙o2max and heart rate were measured with an incremental 4x200-m test. Training load was estimated using TRIMPc and session RPE. Initial measures (PRE) were repeated immediately (POST) and once weekly on return to SL (PostW1 to PostW4). tHbmass was measured in duplicate at PRE and once weekly during the camp with CO rebreathing. Effects were analyzed using mixed linear modeling.

RESULTS:

TT100 or TT200 was worse or unchanged immediately POST, but improved by ∼3.5% regardless of living or training at SL or altitude following at least 1 week of sea level recovery. Hi-HiLo achieved a greater improvement two (5.3%) and four weeks (6.3%) after the camp. Hi-HiLo also improved more in TT400 and TT50 two (4.2% and 5.2%, respectively) and four weeks (4.7% and 5.5%) from return. This performance improvement was not linked linearly to changes in V˙o2max or tHbmass.

CONCLUSION:

A well- implemented 3- or 4-week training camp may impair performance immediately, but clearly improves performance even in elite swimmers after a period of SL recovery. Hi-HiLo for 4 weeks improves performance in swimming above and beyond altitude and SL controls, through complex mechanisms involving altitude living and SL training effects.


 2015 Feb 24. [Epub ahead of print]

Effects of Altitude on Performance of Elite Track-and-Field Athletes.

Abstract

PURPOSE:

Lower barometric pressure of air at altitude can affect competitive performance of athletes in some sports. Here we report the effects of various altitudes on elite track-and-field athlete's performance.

METHODS:

Lifetime track-and-field performances of athletes placed in the top 16 in at least one major international competition between 2000 and 2009 were downloaded from the database at tilastopaja.org. There were 132,104 performances of 1889 athletes at 794 venues. Performances were log-transformed and analyzed using a mixed linear model with fixed effects for 6 levels of altitude and random quadratic effects to adjust for athlete's age.

RESULTS:

Men's and women's sprint events (100-400 m) showed marginal improvements of ~0.2% at altitudes of 500-999 m, and above 1500 m all but the 100-and 110-m hurdles showed substantial improvements of 0.3-0.7%. Some middle- and long-distance events (800-10,000 m) showed marginal impairments at altitudes above 150 m, but above 1000 m the impairments increased dramatically to ~2-4% for events >800 m. There was no consistent trend in the effects of altitude on field events up to 1000 m; above 1000 m hammer throw showed a marginal improvement of ~1%, and discus was impaired by 1-2%. Above 1500 m, triple jump and long jump showed marginal improvements of ~1%.

CONCLUSIONS:

In middle-and long-distance runners altitudes as low as 150-299 m can impair performance. Higher altitudes (≥ 1000 m) are generally required before decreases in discus performance, or enhancements in sprinting, triple-and long-jump, or hammer throw are seen.


Saturday, April 18, 2015

Performance during the 2014 FIFA World Cup: download free from BJSM









The association of environmental heat stress with performance: analysis of the 2014 FIFA World Cup Brazil

  • George P Nassis
  • Joao Brito
  • Jiri Dvorak
  • Hakim Chalabi
  • Sebastien Racinais
Br J Sports Med 2015;49:609-613 Published Online First: 17 February 2015

http://bjsm.bmj.com/content/49/9/609.full.pdf+html

Tuesday, February 24, 2015

Does heat affect football performance?


To contribute into this discussion we have analyzed performance data during the 2014 FIFA World Cup BrazilTM in relation to environmental heat stress. A summary of the findings is presented in this table. 


Soon, the full paper will have open access.

Saturday, January 31, 2015

Think different, innovative & act effectively


















Here I am again after a period of silence. This was intentional to re-think the approach. As you can see, I decided to “re-brand” the blog to make it more useful (I hope!). Why this change?

Think different: I believe to make a step forward we need to look at things from a different angle. Not necessarily good but, for sure, we learn a lot.

Think innovative: I know this is a “big” word. Nowadays, many experts talk about innovation. I am not an expert but I think if we learn to look from a different angle or read below the lines we might find some good stuff.

Act effectively: To my experience, this is what is missing in sports & exercise science; the link between science and practice. The trend these years is to move towards “translation research” meaning research that will seek to answer practical questions & which will make the difference on the field. Again, this is not the end of the story. A key step in achieving this translation is the effective communication between the scientists and the practitioners.

Everyone has examples of ineffective plans. As an example, if training load is a key parameter in injury prevention in elite football, why many elite clubs don’t use this tool effectively? If science and medicine have made advancements in injury prevention why the rate of non-contact injuries remains high?

In the public health domain, why the vast majority of people do not take regular physical activity? This is despite the huge number of studies showing that regular physical activity protects from premature death.

Do we miss something?

I am happy to post your thought & ideas under the condition you identify yourself.

Hope you enjoy the posts from today. 

Regards

George

PS: The next 2 posts will be on the two examples I brought to your attention above. Stay tuned!

Friday, September 19, 2014

How to boost performance on the competition day?

Coaches and sport scientists mainly focus on how to train better the days before and recover fasted in the hours/days after training and matches. No doubt that training quality is the foundation of peak performance. Another window of opportunity is the day and hours before competition. What can we do to maximize potential? This is a summary of strategies based on recent evidence:


In the competition day
Warm up: The aim is to elevate muscle and body's temperature at an optimal level. An increase in warm up intensity in the cold days and a reduction in the post-warm up recovery has been shown to improve performance. When time between warm-up and actual start of competition is long, use strategies like passive heat to maintain muscle and body temperature. 

Postactivation potentiation: It can be induced with exercise intensities ranging from 75-95% of 1RM. The optimal recovery period is 8-12min. Research also suggest the use of plyometrics.

Hormonal optimization: This can be achieved by various means such as:
-High-intensity training 3-7 hours before competition
-strength training 3-7 hours before competition (see postactivation potentiation above)
-ischemic training via partial working muscles blood flow restriction.

It must be noted that evidence is very limited so far. Also the existing research is mainly in healthy individuals and not in competitive and, more importantly, high level athletes.

For further reading
Kilduff et al (2013). Int J Sports Physiol Perform

Monday, July 14, 2014

How to use easy to conduct tests for players monitoring: an example



Germany vs Argentina (13/7/2014) fifa.com
 
Acute responses of soccer match play on hip strength and flexibility measures: potential measure of injury risk

Darren J. Paul, George P. Nassis, Rodney Whiteley, Joao B. Marques, Dean Kenneally & Hakim Chalabi Journal of Sports Sciences, 2014 Vol. 32, No. 13, 1318–1323,




http://dx.doi.org/10.1080/02640414.2014.927069 FREE to download from Journal of Sports Sciences (14/7/2014)


Saturday, July 12, 2014

Recent studies on football (FREE to download)

fifa.com
Below you can find some recent papers with practical applications to football (soccer). They are free to download form the journals official sites.

How Small-Sided and Conditioned Games Enhance Acquisition of Movement and Decision-Making Skills. Exercise & Sport Sciences Reviews: July 2013 - Volume 41 - Issue 3 - p 154–161
http://journals.lww.com/acsm-essr/Fulltext/2013/07000/How_Small_Sided_and_Conditioned_Games_Enhance.4.aspx

 

The Influence of Soccer Playing Actions on the Recovery Kinetics After a Soccer Match. 
Journal of Strength & Conditioning Research June 2014 - Volume 28 - Issue 6 - p 1517–1523
 
 
 

Soccer Training Improves Cardiac Function in Men with Type 2 Diabetes.
Medicine & Science in Sports & Exercise December 2013 - Volume 45 - Issue 12 - p 2223–2233
 

Friday, June 20, 2014

How to find the top performers?



We are all wondering how to identify a talent. Meetings, research projects, tests, papers and hard work. We are all doing our best. Here, I post a presentation from Rasmus Ankersen the author of "The Gold Mine effect". Rasmus is not a scientist but he can add a "fresh" look to the problem as an outsider.
I hope you all find this video useful.
Regards
George

http://www.youtube.com/watch?v=yE7F0yiPqgg

Monday, June 2, 2014

Effect of cold water immersion on long term adaptations: time to re-consider the practice?

There was a number of interesting abstracts during the ACSM last week in Orlando, Florida. Today, I would like to comment on the study presented by Roberts and colleagues from Australia which received one of the international student awards.

You might remember that in one of my posts in this blog about 3 years ago, I raised the issue of possible negative impact of frequent cold water immersion (CWI) on long term adaptations to training. For your information this is the post http://georgenassis.blogspot.com/2011/07/some-thoughts-on-use-of-water-immersion.html

This speculation, at that time, was based on the fact that CWI seems to suppress inflammation which is part of the exercise training-induced adaptation process.

The group from Australia tested this idea in 21 men split in two groups. One group performed high-intensity resistance training twice a week for 12 weeks plus lower body CWI for 10min post exercise. The other group performed the same training but instead of CWI they cycled at low intensity for 10min post-training. Training adaptations were assessed by measuring changes in maximal isometric torque and rate of force development (RFD), isokinetic dynamic strength, leg press and knee extension strength.

Their results showed that training-induced changes in isometric torque and isokinetic torque, RFD and knee extension strength were signifi cantly smaller in the CWI group.

Based on these findings, it seems that regular CWI may attenuate the exercise training-induced performance improvements.

Reference
Roberts et al. MSSE 46(5): S192

Sunday, April 20, 2014

Recent studies with applications to real life sporting settings

Vitamin C and E supplementation hampers cellular adaptation to endurance training in humans

FREE to download from the Journal of Physiology



Paulsen et al. J Physiol 2014;592:1887-1901



Abstract
In this double-blind, randomised, controlled trial, we investigated the effects of vitamin C and E supplementation on endurance training adaptations in humans. Fifty-four young men and women were randomly allocated to receive either 1000 mg of vitamin C and 235 mg of vitamin E or a placebo daily for 11 weeks. During supplementation, the participants completed an endurance training programme consisting of three to four sessions per week (primarily of running), divided into high-intensity interval sessions [4-6 × 4-6 min; >90% of maximal heart rate (HRmax)] and steady state continuous sessions (30-60 min; 70-90% of HRmax). Maximal oxygen uptake (VO2 max ), submaximal running and a 20 m shuttle run test were assessed and blood samples and muscle biopsies were collected, before and after the intervention. Participants in the vitamin C and E group increased their VO2 max (mean ± s.d.: 8 ± 5%) and performance in the 20 m shuttle test (10 ± 11%) to the same degree as those in the placebo group (mean ± s.d.: 8 ± 5% and 14 ± 17%, respectively). However, the mitochondrial marker cytochrome c oxidase subunit IV (COX4) and cytosolic peroxisome proliferator-activated receptor-γ coactivator 1 α (PGC-1α) increased in the m. vastus lateralis in the placebo group by 59 ± 97% and 19 ± 51%, respectively, but not in the vitamin C and E group (COX4: -13 ± 54%; PGC-1α: -13 ± 29%; P ≤ 0.03, between groups). Furthermore, mRNA levels of CDC42 and mitogen-activated protein kinase 1 (MAPK1) in the trained muscle were lower in the vitamin C and E group than in the placebo group (P ≤ 0.05). Daily vitamin C and E supplementation attenuated increases in markers of mitochondrial biogenesis following endurance training. However, no clear interactions were detected for improvements in VO2 max and running performance. Consequently, vitamin C and E supplementation hampered cellular adaptations in the exercised muscles, and although this did not translate to the performance tests applied in this study, we advocate caution when considering antioxidant supplementation combined with endurance exercise.

Burns KJ, Pollock BS, Lascola P, McDaniel J. Cardiovascular responses to counterweighted single-leg cycling: implications for rehabilitation. Eur J Appl Physiol. 2014 May;114(5):961-8. 

Abstract
PURPOSE: Although difficult to coordinate, single-leg cycling allows for greater muscle-specific exercise capacity and subsequently greater stimulus for metabolic and vascular adaptations compared to typical double-leg cycling. The purpose of this investigation was to compare metabolic, cardiovascular and perceptual responses of double-leg cycling to single-leg cycling with and without the use of a counterweight. METHODS: Ten healthy individuals (age 22 ± 2 years; body mass 78.0 ± 11.2 kg; height 1.8 ± 0.1 m) performed three cycling conditions consisting of double-leg cycling (DL), non-counterweighted single-leg cycling (SLNCW) and single-leg cycling with a 97 N counterweight attached to the unoccupied crank arm (SLCW). For each condition, participants performed cycling trials (80 rpm) at three different work rates (40, 80 and 120 W). Oxygen consumption (VO2), respiratory exchange ratio (RER), heart rate (HR), femoral blood flow, rating of perceived exertion (RPE) and liking score were measured. RESULTS: VO2 and HR were similar for DL and SLCW conditions. However, during SLNCW, VO2 was at least 23 ± 13 % greater and HR was at least 15 ± 11 % greater compared to SLCW across all three intensities. Femoral blood flow was at least 65.5 ± 43.8 % greater during SLCW compared to DL cycling across all three intensities. RPE was lower and liking scores were greater for SLCW compared to SLNCW condition. CONCLUSION: Counterweighted single-leg cycling provides an exercise modality that is more tolerable than typical single-leg cycling while inducing greater peripheral stress for the same cardiovascular demand as double-leg cycling.


Nilstad A, Bahr R, Andersen TE. Text messaging as a new method for injury registration in sports: a methodological study in elite female football. Scand J Med Sci Sports. 2014 Feb;24(1):243-9.

Abstract
Methodological differences in epidemiologic studies have led to significant discrepancies in injury incidences reported. The aim of this study was to evaluate text messaging as a new method for injury registration in elite female football players and to compare this method with routine medical staff registration. Twelve teams comprising 228 players prospectively recorded injuries and exposure through one competitive football season. Players reported individually by answering three text messages once a week. A designated member of the medical staff conducted concurrent registrations of injuries and exposure. Injuries and exposure were compared between medical staff registrations from nine teams and their 159 affiliated players. During the football season, a total of 232 time-loss injuries were recorded. Of these, 62% were captured through individual registration only, 10% by the medical staff only, and 28% were reported through both methods. The incidence of training injuries was 3.7 per 1000 player hours when calculated from individual registration vs 2.2 from medical staff registration [rate ratio (RR): 1.7, 1.2-2.4]. For match injuries, the corresponding incidences were 18.6 vs 5.4 (RR: 3.4, 2.4-4.9), respectively. There was moderate agreement for severity classifications in injury cases reported by both methods (kappa correlation coefficient: 0.48, confidence interval: 0.30-0.66).



Areta JL, Burke LM, Camera DM et al. Reduced resting skeletal muscle protein synthesis is rescued by resistance exercise and protein ingestion following short-term energy deficit. Am J Physiol Endocrinol Metab 2014;306:E989-997

Abstract
The myofibrillar protein synthesis (MPS) response to resistance exercise (REX) and protein ingestion during energy deficit (ED) is unknown. In young men (n = 8) and women (n = 7), we determined protein signaling and resting postabsorptive MPS during energy balance [EB; 45 kcal·kg fat-free mass (FFM)(-1)·day(-1)] and after 5 days of ED (30 kcal·kg FFM(-1)·day(-1)) as well as MPS while in ED after acute REX in the fasted state and with the ingestion of whey protein (15 and 30 g). Postabsorptive rates of MPS were 27% lower in ED than EB (P < 0.001), but REX stimulated MPS to rates equal to EB. Ingestion of 15 and 30 g of protein after REX in ED increased MPS ∼16 and ∼34% above resting EB (P < 0.02). p70 S6K Thr(389) phosphorylation increased above EB only with combined exercise and protein intake (∼2-7 fold, P < 0.05). In conclusion, short-term ED reduces postabsorptive MPS; however, a bout of REX in ED restores MPS to values observed at rest in EB. The ingestion of protein after REX further increases MPS above resting EB in a dose-dependent manner. We conclude that combining REX with increased protein availability after exercise enhances rates of skeletal muscle protein synthesis during short-term ED and could in the long term preserve muscle mass.


Saturday, April 19, 2014

Who is leading the change in a Club or Organization?


Look at the best clubs and the best teams in the world, being in sport or other sector. What do they have in common?

Someone might say that it is the players/employees who make the difference in a team or organization. I would agree, at least in part. No change will happen if the CEO or the Board of Directors or the Head Manager, whoever is leading the team/organization, are not ready for the change and are not convinced about the “where to go”.

The leader will develop the vision & the strategic plan, he will communicate it with all people involved and will inspire them to work hard every day for the common purpose.

If (the leader) has a clear vision he will place the right people at the right position. This will be one of the first steps for a successful journey.

Take home message
Next time choose your manager!

For further reading
Jim Collins. Good to Great. Harper Business, 2001

Anita Elberse with Sir Alex Ferguson. Ferguson's formula. Harvard Business Reviews, October 2013 http://hbr.org/2013/10/fergusons-formula/ar/1  

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 

Saturday, February 22, 2014

Is cold water immersion beneficial or harmful to long-term performance improvement?


 
wikipedia
Cold water immersion (CWI) is a popular means for athletes recovery. Although most of the studies report an improved feeling of fatigue following CWI, not all of them agree on the performance benefits. The aim of this post is to stimulate the discussion on the effect of repeated sessions of cold water immersion on performance and adaptations to training.

As you may remeber I published a post in July 2011 challenging the concept of CWI as a means of recovery in athletes http://georgenassis.blogspot.com/2011/07/some-thoughts-on-use-of-water-immersion.html. The idea was that CWI, which reduces exercise-induced inflammation, may result in attenuated adaptations to training. Let me remind you that exercise-induced inflammation is a "trigger" to adaptations and hence every method that reduces inflammation would affect adaptations to training in a negative way.

The study by Halson et al. (2014) published few days ago in Medicine & Science in Sports and Exercise tested the effect of repeated CWI sessions on performance of trained cyclists. Their results showed that, following 39 days of training, cyclists in the CWI condition did not show performance impairement compared with the control group. This data do not support the speculation that prolonged use of CWI may attenuate adaptations to training. I am sure you will build your own opinion by reading the paper, but there are 2 points I would like to raise; the first point is that CWI did not produce any performance benefit compared with the control condition in this study. So, what's the reason of using CWI besides the players/athletes satisfaction? The second point is that we still don't know what might happen with longer exposure to CWI.

In another study, volunteers had one limb in cold water post training while the other leg was not cooled (Fröhlich et al., 2014). The individuals performed strength training for both legs for a period of 5 weeks. The results of the study showed a tendency for greater strength gains in the control group.

Overall, these recent findings highlight the need for more studies on the effect of repeated CWI sessions on long-term performance. Given that it is difficult to have high performance athletes in these experiments, studies with competitive athletes would help a lot.

For more reading
 Halson SL1, Bartram J, West N, Stephens J, Argus CK, Driller MW, Sargent C, Lastella M, Hopkins WG, Martin DT. Does Hydrotherapy Help or Hinder Adaptation to Training in Competitive Cyclists? Med Sci Sports Exerc. 2014 Feb 5. [Epub ahead of print]

Fröhlic M, Faude O, Klein M, Pieter A, Emrich E, Meyer T. Strength training adaptations after cold water immersion. J Strength Cond Res. 2014 Feb 18. [Epub ahead of print]

http://georgenassis.blogspot.gr/2011/10/post-training-muscle-cooling-may.html