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Wednesday, March 15, 2017

What have we learned from UEFA Champions League so far?

uefa.com
We are reaching the end of the round of 16, with 2 matches missing tonight, and here I have summarized lessons to be learned so far.

Lesson 1: Don’t always trust the numbers: From a data analysis perceptive Sevilla FC could have won the match yesterday. Compared to Leicester City FC, they had more ball possession (68% vs 32%), more passes completed (531 vs 199!), higher passes accuracy (86% vs 70%) and more attempts on target (5 vs 4). In addition, Sevilla players covered greater distance running compared to Leicester (106.2 km vs 104.4 km). Though, Sevilla lost the match! Last week, PSG players covered much greater distance in the field (110.4 km vs 105.8 Km) though they were defeated by FC Barcelona. Match winning is so complex and affected by not only technical and physical elements but also other factors like players’ desire to win (!), robustness of the team, fans’ support.

uefa.com



So, what’s going on? Are the data we collect (huge amounts indeed) useless? No, this is not the case. Data are needed and will assist in making more intelligent solutions. It’s not about the data; It’s about how you interpret the numbers. Smart data interpretation require the ability to read the context!

Bottom line; numbers have a meaning when someone attempts to interpret them looking at the context. In one of our papers we have addressed the issue of critical thinking in football performance and I suggest you have a look should you are more interested in this area. Here is the link https://www.researchgate.net/publication/273071207_Factors_Affecting_Match_Running_Performance_of_Elite_Soccer_Players_Shedding_Some_Light_on_the_Complexity?ev=prf_pub


Lesson 2: Smart planning leads to success. Leicester are not doing well in the English Premier League but they are very successful in the Champions League. I assume the Club has made a decision right from this season’s beginning and prioritized the objectives based on the team’s strengths and weaknesses.

Lesson 3: Smart support may raise the team to a higher level. I am sure you all agree Leicester FC have been a successful example of smart planning and decision making at all levels. Science and medical staff play a role in this success story. Proper training and recovery periodization and injury prevention strategies are key action plans that can add value and boost the team's performance to a higher level.

To learn more about how this is happening in Leicester City FC I advise you to watch the video with the Head of Sports Science speaking https://www.youtube.com/watch?v=_7Rsdj-_AoI&feature=youtu.be&list=PL8z05aMc--mi4LZb2wynvSYUqlR1ou20

To learn more on how intelligent approaches may help the team to achieve more, you can have a look at resources below

-effective recovery strategies https://www.ncbi.nlm.nih.gov/pubmed/23315753







Friday, February 17, 2017

高温环境中训练和比赛的共识性建议 (Consensus Recommendations on Training and Competing in the Heat)




source:johnsonfitness

Our paper published in Chinese (Clin J Sports Med 2016) FREE to download from the link below
http://cbimg.cnki.net/Editor/2016/0309/ydyx/8e8c1979-3de0-4c98-8bb5-6784610f8c60.pdf

Consensus Recommendations on Training and Competing in the Heat
Original Authors:Sébastien Racinais,Juan-Manuel Alonso,Aaron J. Coutts,Andreas D. Flouris,Olivier Girard,José González -Alonso,Christophe Hausswirth,Ollie Jay,Jason K. W. Lee,Nigel Mitchell,George P. Nassis,Lars Nybo,Babette M. Pluim,Bart Roelands,Michael N. Sawka,Jonathan Wingo,Julien D. Périard.

For those who don't speak Chinese, the English version is FREE to download here https://www.researchgate.net/publication/278327658_Consensus_recommendations_on_training_and_competing_in_the_heat

Monday, February 13, 2017

Competencies required by effective strength & conditioning coaches

http://articles.mcall.com/2014-01-06/sports/mc-penn-state-football-coach-0106-20140106_1_miami-coach-al-golden-strength-coach-vanderbilt-coach-james-franklin

Effective strength and conditioning coaching is a complex series of actions that require competencies across a wide range of areas. The below article by Dr, Ian Jeffreys explores our understanding of effective coaching using Gardner's Five minds.

The article can been found here

Enjoy reading!
Warm regards
George

Saturday, February 11, 2017

Vacancy in High Performance-Human Performance Specialist, Williams F1



Human Performance Specialist
Williams F1

More information about this job: 

Overview:

We are currently seeking a Human Performance Specialist to join our Race Team on a full time basis. Reporting to the Head of Health and Human Performance, and the Sporting Manager when travelling, the successful candidate will be responsible for maintaining and developing the current physical performance programme for the Williams Race Team. The role also requires an element of psychological coaching in order to ensure individual performance in high pressure environments. With support from the Health and Human Performance team at the factory, the successful candidate will facilitate a data-informed approach to fitness training and performance analysis therefore experience with biometrics or similar statistical analysis is preferred. 
More information here


Monday, October 31, 2016

Outsiders’ intelligence: Time to re-think current practices?










“If nothing is going right, turn left”
Anonymous


We live in an era of accelerated knowledge. In modern elite level sports and in particular in football, input from the backroom staff (medicine and science practitioners) is considerable and influences the coaches’ decision-making process. However, it appears that there is a huge gap between knowledge gained in the lab or via research and actual benefit for the team in the field. As an example, injuries incidence in elite football players remained unchanged over the last 10 years. This was despite the growing number of scientific papers on prevention over the same period and the fact that some clubs are using injury prevention programs regularly. Another example, again in elite football, is related to the effect of congested fixture on performance. As most of you know, congested fixture will possibly result in performance decrements despite the fact that training and recovery methods have been substantially improved over the last years. Are we heading in the right direction? Should we start thinking differently?

Why injuries incidence remains stable?
With reference to the first example above, a number of reasons may explain the relatively low effectiveness of injury prevention programs on the injury incidence in elite football. Some of these factors are: the lack of applied research which is real-life questions driven, the inability to translate current research into effective practice, the relatively low players’ compliance with the prevention training. If player’s commitment with the specific exercise program is an issue (as some researchers and practitioners suggest) we should concentrate more on understanding our players rather than on developing exercise drills. Knowledge from social sciences might help in understanding our players better. In extension to that, it is assumed that the lack of fresh ideas and of the 360o view might also be a factor. As in other expertise knowledge from other areas, outsiders’ knowledge, could add value and help in finding solutions to current challenges.

What can we learn from the outsiders?
In terms of injury prevention and risk detection approaches in elite footballers, the majority of strategies so far are fragmented. Screening tests, mostly performed at the start of season and in isolation to the game context, are correlated with the injury incidence throughout the season. However, to link any injury with its risk factors we should at least analyze the specific movement and the context (e.g. time of match, style of play) that it occurs. For that reason, we must integrate measures and data from movement and performance analysis, energy system function, psychological status and previous training principles. This requires a dynamic and holistic approach in data analysis. Several business units of a dynamic nature use approaches to deal with big data and reach meaningful conclusions, being, for instance, the risk of taking a decision, prices/budget forecasts, consumers behavior etc. I am sure that modern sports have to learn a lot from these practices.
USA navy wanted to use the most advanced tools to screen their pilots’ ability to perform well under high psychological stress. This initiative was driven by the strategic objective to reduce the human lives losses and financial cost in case of fatal events. Their research showed that certain proteins are valid candidate molecules to identify individuals who can perform well while under high stress. I am not claiming that we should use exactly the same genomic approach as in pilots but this knowledge from outsiders might help us to improve the tools we use in football.

Football can learn from top business
Business owners in the City of London wanted to know which biological factors affect the traders’ decision making. If they are able to identify the influential biological markers next step would be to manipulate them towards the optimal level. Saliva samples were collected from the traders every morning and were analyzed for testosterone and cortisol concentration. The saliva hormones daily variations were plotted against their performance (money profit and losses). The results showed that the traders were making profits in the days that testosterone concentration was high. This is particularly relevant to elite sports where all actions should align to optimize performance at a certain time of day.

What’s next?
To my view we should rethink the way we approach, plan and execute science in modern sports. To provide effective solutions to coaches/managers, being tools to injury incidence reduction and performance enhancement, we should also look at other areas and places. Knowledge from outsiders might help.



George Nassis holds a doctorate degree in exercise physiology & sports science and has long experience as a physiologist and head of performance in football. He has extensive experience on the integration of sports medicine and science for injury prevention and performance enhancement. George has published more than 50 papers in peer-reviewed scientific journals (h-index=18). 

Monday, July 20, 2015

Does regular post-exercise cold application attenuate training adaptations?

That's a fundamental questions asked by many coaches and practitioners over the last year(s) (http://georgenassis.blogspot.gr/2011/07/some-thoughts-on-use-of-water-immersion.html). This concern is growing as more data is published showing that regular cold application might attenuate training adaptations.


What's new?
Yamane and colleagues (2015) asked their participants to train with wrist flexion exercises, 3 times a week for 6 weeks. Seven subjects immersed their forearms in cold water (10 ± 1°C) for 20 min after each training whereas the other 7 didn't immerse their limbs. Their results showed that regular post-exercise cold application attenuated muscular and vascular adaptations to this type of training (http://www.ncbi.nlm.nih.gov/pubmed/25760154).

In a more recent study, 21 active males participated in a strength training program for 12 weeks. Post-exercise recovery included either 10-min cold water immersion (CWI) or active recovery. Their results showed that CWI attenuates the exercise training induced hypertrophy (http://www.ncbi.nlm.nih.gov/pubmed/26174323).

Points to consider
Although both studies provide novel data on the potential role of regular post-exercise cold water immersion on training adaptations, they are not without limitations. Their main limitation is that participants were non-trained and, thus, we don't know if these results apply to trained individuals.

Evidence against 
On the other side, Ihsan et al. (2015) recently showed that regular cold water immersion following endurance training sessions may enhance mitochondrial biogenesis (http://www.ncbi.nlm.nih.gov/pubmed/26041108). As in the above mentioned studies, non-trained subjects were recruited and this limits the applications of these findings.


Take-home message
My opinion is that there is evidence that regular post-exercise cold application attenuates adaptations to training. We should acknowledge however that this information comes from non-trained males following strength training. Until more data in trained and possibly elite individuals are published we should be more concerned with the regular application of cold as a means of recovery.

Friday, July 10, 2015

Training load assessment in elite football players: should we trust what we read?

with Djibril Cisse  (Pre-season camp in Austria, July 2010)

As most of you know, training load (TL) assessment is vital to injury prevention strategy development. There are various tools of TL assessment, with the Rate of Perceived Exertion being one of the most popular. 

In one of our papers (Brito, Hertzog, Nassis 2015), accepted for publication last week, we analysed the TL of highly trained football players daily throughout the entire season. The fatigue index was assessed once per week for the same period. 

Our main finding was that training load was affected by a number of factors like previous and next match result and location. In addition, although TL fluctuated throughout the year the fatigue index remains relatively stable. Given the limitations of our methodology, we speculate that highly-trained players choose their pace during training in order to avoid excess fatigue throughout the season.

Practical implications

1) RPE-based training load assessment may not be as accurate as we think, and 
2) highly-trained players have the ability to modify their pace in order to avoid excessive fatigue. Although this speculation remains to be proved with more robust experimental designs, our data suggest we should consider modifying our strategies on fatigue & injury prevention.

The abstract of this study can be reached at 

Friday, June 12, 2015

Post-exercise recovery: time to reconsider our practice?

sports.ndtv.com

Following the last week's post (here http://georgenassis.blogspot.com/2015/06/cold-water-immersion-is-it-all-in-our.html), I have received a number of emails with valid comments. Thank you all for that!

It is evident that post-exercises strategy is a "hot" topic in sports. There is substantial literature on that topic. Does this knowledge makes a big difference in the field? 

Based on my experience, there is need for more work on the applicability of the post-recovery strategies in a real life set-up. For instance, players' compliance to some recovery methods is variable, if not low, at some periods. This is of course a fact that affects the methods' effectiveness.

In a previous post, I highlight the findings of a study that examined player's perception on recovery methods and the effectiveness of these methods on recovery (here http://georgenassis.blogspot.com/2012/07/which-is-most-effective-recovery-method.html).

To summarize my thoughts, I believe that:
  • we need to implement a more holistic approach by applying various methods depending on the athlete's belief and the period of the year
  • we must improve players buy-in. If athletes believe on the method, they will comply and this might result in better recovery.


Again, your contribution is very much appreciated.

Regards
George

Friday, June 5, 2015

Cold water immersion for recovery: is it all in our mind?

greekamericannewsagency.com


Cold water immersion is a very popular strategy for recovery after exercise. Although there is evidence on its benefits on perception of fatigue no consensus exists on its effect on performance. In addition, many studies show no effect of this strategy on physiological functions. Part of the confusion might be due to the studies' design. Indeed, most studies have not used a placebo condition and this could have affected the conclusion and hence the practical applications.

The study of Broatch et al (2014) investigated if the placebo effect is responsible for any acute performance and psychological benefit of postexercise cold water immersion. Following a high-intensity interval session, the participants followed one of the 3 following recovery conditions i) cold water immersion at 10 oC, ii) thermoneutral water immersion placebo (34.7 oC), iii) thermoneutral water immersion control (34.7 oC). 

Their conclusion was that a recovery placebo administered after high-intensity exercise was as effective as cold water immersion in the recovery of muscle strength over 48 hours. In addition, both the cold water and the thermoneutral immersion placebo resulted in faster recovery of strength compared with the control condition.

This study shows that at least part of any benefit of cold water immersion is due to a placebo effect.


How this study might affect practice?

  • Postexercise water immersion even at around 30 oC may produce similar performance improvements compared to cold water immersion provided we lead athletes believe that thermoneutral water immersion is beneficial on performance recovery.
  • Medical & sports science staff should not be so concerned about the water temperature itself. 
  • Thermoneutral water immersion is more comfortable to athletes and this should be taken into consideration when planning a recovery strategy.


Some concerns

  • This study examined the recovery of muscle strength. We don't know what might happen with the application of the same recovery strategy on other performance parameters such as speed, repeated sprints ability and endurance.


Source
Broatch et al (2014). Med Sci Sports Exerc, 46(11):2139-47.


Friday, May 15, 2015

Training or competing in the heat: how to protect your health & boost performance?

healthline.com
In the below article you can find the most recent update on recommendations for event organizers, athletes, coaches and scientists. You can download free from the Scandinavian Journal of Medicine & Science in Sports at
http://onlinelibrary.wiley.com/doi/10.1111/sms.12467/epdf

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.