Tuesday, September 6, 2011

Troubles with RSA

I was just finishing reading great review paper(s) on Repeated-Sprint-Ability by Girard, Bishop and Mendez-Villanueva.

Girard O, Mendez-Villanueva A, Bishop D. Repeated-sprint ability - part I: factors contributing to fatigue. Sports Med. 2011 Aug 1;41(8):673-94.

Bishop D, Girard O, Mendez-Villanueva A. Repeated-Sprint Ability - Part II: Recommendations for Training. Sports Med. 2011 Sep 1;41(9):741-56.

Me reading the studies during my day off...  I always pay attention to RSA :)
 
Mentioned papers are great up-to-date review of the current knowledge on RSA testing and training. Here are some quotes from the papers:

For example, the limited evidence to date suggests that, compared with repeated- or intermittent-sprint training, interval training produces superior increases in both βmin vitro  [27] and Na+/K+ pump isoform content.[12] With respect to RSA, repeated-sprint training has been reported to produce greater improvements in best sprint time[12,27,96] and mean sprint time,[4,12,27,96] compared with interval-based training. In contrast, interval training appears to be superior to repeated-sprint training to decrease (i.e. improve) the sprint decrement score (or the fatigue index).[12,27] However, due to the problems associated with interpreting changes in the sprint decrement score when there are concurrent changes in best sprint time,[102] it is difficult to make universal recommendations.

Thus, it appears that while interval training may be superior at minimizing the decrement during repeated sprints (possibly due to greater physiological adaptations, as outlined in section 2),  intermittent- or repeated-sprint training is superior at improving the performance of individual sprints. As a result, the combination of  the two (i.e. repeated-sprint training to improve sprint performance plus interval training to improve the recovery between sprints) may be the best strategy to improve RSA. Further research is required to investigate the optimal volume and duration of a repeated-sprint training macro cycle, as anecdotal evidence suggests that too much repeated-sprint training is stressful and may lead to decreases in RSA.

Despite the obvious need of more research in this area, these results seem to confirm that in well trained team-sport athletes, maximization of mean repeated-sprint time is linked to improvements in single-sprint performance.[33]

This review has highlighted that there is not one type of training that can be recommended to best improve RSA and all of the factors believed to be responsible for performance decrements during repeated-sprint tasks

While different training strategies can be used in order to improve each of these potential limiting factors, and in turn RSA, the concurrent implementation of different forms of training may be the best strategy to improve RSA

Nonetheless, two key recommendations can be made based on the existing literature as follows:
1. It is important to include some training to improve single-sprint performance. This should include (i) specific sprint training; (ii) strength/power training; and (iii) occasional high-intensity(>VO2max) training (e.g. repeated, 30-second, allout efforts separated by ~10 minutes of recovery) to increase the anaerobic capacity.

2. It is also important to include some interval training to best improve the ability to recover between sprints (if the goal is to improve fatigue resistance). High-intensity (80–90% VO2max) interval training, interspersed with rest periods (e.g.1 minute) that are shorter than the work periods (e.g. 2 minutes) is efficient at improving the ability to recover between sprints by increasing aerobic fitness (VO2max and the lactate threshold), the rate of phosphocreatine resynthesis and βmin vitro

What I wanted to rant about in this blog entry are not the training implications (which are mentioned in the quotes above, but I will deal with them in another blog entry), but rather assessment and evaluation of RSA performance. What is better and what is worse? How do we evaluate the RSA performance?

There are couple of methods to evaluate the RSA performance. Suppose we have an athlete that did 5x30m runs with 25sec jog back recovery. His times are as follows:


Sprint
Athlete A
1
4,7
2
4,7
3
4,75
4
4,8
5
4,82
Total time
23,77
Average
4,754
Best
4,7
Worst
4,82
FI (%)
2,49%
Sdec (%)
1,15%

 
From the mentioned data we are going to calculate Total Time (basic sum of all sprints), Average Time, Fatigue Index (FI) and Percentage Decrement Score (Sdec). If you are interested how is this calculated please check the mentioned papers, but to understand what I want to argue you don’t basicaly need to know.

So, this Athlete A shows certain pattern of fatigue (shown by FI and Sdec) as the sprints repeat. Let’s introduce Athlete B. 



Sprint
Athlete A
Athlete B
1
4,7
4,77
2
4,7
4,77
3
4,75
4,77
4
4,8
4,77
5
4,82
4,77
Total time
23,77
23,85
Average
4,754
4,77
Best
4,7
4,77
Worst
4,82
4,77
FI (%)
2,49%
0,00%
Sdec (%)
1,15%
0,00%


            What we can see in the case of Athlete B is that he has great ability to repeat the sprints without fatigue (as shown by zero score in his FI and Sdec ). His first sprint was slower, but he maintained it across sprints.

            Let me introduce Athlete C.



Sprint
Athlete A
Athlete B
Athlete C
1
4,7
4,77
4,3
2
4,7
4,77
4,4
3
4,75
4,77
4,5
4
4,8
4,77
4,6
5
4,82
4,77
4,7
Total time
23,77
23,85
22,5
Average
4,754
4,77
4,5
Best
4,7
4,77
4,3
Worst
4,82
4,77
4,7
FI (%)
2,49%
0,00%
8,51%
Sdec (%)
1,15%
0,00%
4,65%


            The Athlete C has the fastest first sprint, but he fatigues as hell across the sprints (as shown by his FI and Sdec ). 

Now the main question: Who has better Repeated-Sprint-Ability? Athlete A, B or C? Who would you like in your team? If this is all one athlete, would you like his RSA progress from A to B, or from A to C over time? Why?

            If we take FI and  Sdec as an indice of RSA ability, then Athlete B would be our best bet. But hell, he has „Repeated-Slow-Ability“ (TM) as my brother-in-arms Carl Valle would say. He is slow as hell. Look at his average and total time – they are worst from the three.
           
            Let me tell you straight. I would choose Athlete C to be in my team. His first sprint is way better than of other two, his total time is better, his average time is better. His last sprint is faster than first sprints of other two guys, even if his FI and Sdec  are worst.

            So what is a indicator of RSA? Ability to recover between slow sprints? Ability to repeat crap power output? I see a lot of athletes and their coaches with crap power output and speed/acceleration working on their RSA. What exactly do they want to be able to repeat? Repeated-Slow-Ability?

            The point being taken here is that we need to see the whole picture. Usual indicator of RSA are FI and Sdec , but hopefully you now see they don’t tell the whole story. If the Athlete C improve both FI and Sdec over time, his RSA will improve. But we cannot compare athletes solely based on FI and Sdec without taking Total Time, Best time and Average into account as well. Just compare Athlete B and Athlete C.

            Now return to the quotes from the article one more time. Especially this one:

Despite the obvious need of more research in this area, these results seem to confirm that in well trained team-sport athletes, maximization of mean repeated-sprint time is linked to improvements in single-sprint performance.[33]

            So, me as a coach want a freaking powerful and quick athlete that is able to produce great single-sprint performance FIRST before I start to be concerned with his RSA. A lot of soccer coaches work on RSA performance, but look at those sprint numbers. They are CRAP. I don’t want my athletes have great FI and Sdec and crap first sprint. I want them to be more like an Athlete C. I will deal with RSA later.

            Regarding training, please read the quotes again. Certain pattern emerges (as sumarized in the last quote) – interval training seems to improve FI and Sdec(recovery between sprints), while repeated-sprint training seems to improve performance of individual sprints (and as concesquence Total Time and Average Time). But what is the latter RSA training is changed for real speed/power training? Would it yield better effects on RSA indices?

To date, we are unaware of research that has investigated the influence of ‘traditional’ sprint
training on RSA. However, it is possible that such training may produce even better improvements in both best sprint time and mean sprint time,[86] and further research is warranted

            Well, maybe we have pushed RSA training drills way over the border. Maybe we don’t need to do more that occasional RSA training sessions („..as anecdotal evidence suggests that too much repeated-sprint training is stressful and may lead to decreases in RSA”) if we do quality strength, power, speed and interval (VO2max) training session?  Maybe RSA (training) is over-rated? 

9 comments:

  1. It's not over-rated unless you miss the forest for the trees. Clearly a guy with good RSA But low speed is not any good. Neither is a guy with top speed and no ability to repeat it. You need both and should train specifically and appropriately.

    It's like power vs. capacity in endurance sports. They are distinct entities and have to be trained in distinct ways. Both are important and which should be focused on depends on the athlete.

    So it's not that RSA is 'over-rated'. It's just that no single modality can possibly cover all training needs.

    ReplyDelete
  2. Hey, cool post. I think are you missing an important point though. What happens if a sports contest extends to "30 sprints"? Athlete C will probably be the worst athlete of the group What sort of training would you recommend for Athlete C at that point?

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  3. Dear dmaxashman,

    Good question and it goes pretty well with Lyle posted.

    RSA is NOT a game pattern in the first place, but rather a situation that emerges during the game couple of times (I guess Gamble/Gabbett did time-motion analysis and searched for RSA pattern in couple of papers). What is interesting is correlation between RSA performance (Total Time, FI, Sdec) and distances covered in a game (especially at higher intensity).

    With this post I didn't wanted to negate or downgrade the importance of RSA (TESTING) or endurance training. I wanted to point out to two things:
    1. We need to see forest AND the trees (like Lyle said). Thus we need to know the first sprint performance, total time, FI and Sdec. Thing needs to be put into context. My opinion is that nomenclature for RSA should be:

    First Sprint Time or Best Sprint (Sdec)
    i.e. Athlete 4,3s (4,65%)

    2. That the best training for RSA performance may not be RSA activity, but some other smart combination of speed/power/strength, interval training, glycolytic training and occassional RSA drills. But, if you follow my blog I guess you have noticed this already.

    3. To warn against trying to improve RSa performance without thinking about speed/power qualities.

    Thanks for input guys!

    ReplyDelete
  4. They might be a correlation between RSA and distance covered just like getting better values of VO2max, however this is just one part of training protocols and some research claimed actual no-correlation between atheltic ability and performance on the field:
    http://www.sciencedaily.com/releases/2011/06/110630220002.htm

    That is, various organismic costraints will shape different strategies on the field thus one guy with poor RSA values might does more passes than guy with high RSA.

    I agree however, that speed/power/strength would be good option to improve RSA.

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  5. I can see RSA being new VO2max. And I fear it will stick for longer.
    Scientist are always looking for things that are measurable (the easier it is to measure something the better), because this is their work - to publish. The more data you can get the easier it is to publish. RSA is simple when it comes to getting the data, much simplier than VO2max.
    But as others have noted - RSA is more questions than answers.
    Which athlete is better?
    How do you improve RSA?
    Is there a correlation between RSA and passes/distance covered/whatever?
    How do you measure RSA? 5/10/50 sprints? Breaks? Distances? - test protocol can change athlete evaluation results
    How do you interpret the results? = Which factors are important?
    Also how often are you repeating your best sprint in a game?
    All things are mixed, and all things are important to some extent, simple game, so many questions and unknowns - I guess that's the beauty of it.

    ReplyDelete
  6. Blasphemy!
    :)

    Nowadays it is crucial in my opinion to based training session on strong scientific principles and I am reffering not only to athletic principles but also methodology and motor learning.

    As a coach, I kind of understand your point Grzesiek, based on protocol, changes might happen, but it is good because without science one would have not known about it thus one might choose other options and evaluations.

    BTW, are you from Poland?

    ReplyDelete
  7. I agree that training should be reasonable and sound at least. I'm not anti-science type of person, don't get me wrong, but I certainly agree with Mladen that results are contex dependend.
    Let's take athlete A and C and compare 8th to 10th sprint times (assume that's how we test athletes and interpret the results), now let's take as test results their 2nd and 3rd times. Results differ slightly, right?
    What I fear most is overreliance on one thing only. This was the case with VO2 protocols few years ago. I guess that people will start to preach RSA as the new holy grail of training.
    And as has been said let's not forget that neither VO2 nor RSA explains the game entirely. Let's not forget that correlation is only that - correlation.
    I'm just amazed that coaches try to be up to date too much and forget about being reasonable first.
    Actually I live in Warsaw. Great I'm not the only one here.

    ReplyDelete
  8. I mentioned and article by Gabbett, thus here it is:

    J Strength Cond Res. 2008 Mar;22(2):543-52.
    Time-motion analysis of small-sided training games and competition in elite women soccer players.
    Gabbett TJ, Mulvey MJ.
    Source

    Brisbane Broncos Rugby League Club, Queensland, Australia. timg@broncos.com.au
    Abstract

    We investigated the movement patterns of small-sided training games and compared these movement patterns with domestic, national, and international standard competition in elite women soccer players. In addition, we investigated the repeated-sprint demands of women's soccer with respect to the duration of sprints, number of sprint repetitions, recovery duration, and recovery intensity. Thirteen elite women soccer players [age (mean +/- SD) 21 +/- 2 years] participated in this study. Time-motion analysis was completed during training (n = 39) consisting of small-sided (i.e., three versus three and five versus five) training games, domestic matches against male youth teams (n = 10), Australian national-league matches (n = 9), and international matches (n = 12). A repeated-sprint bout was defined as a minimum of three sprints, with recovery of less than 21 seconds between sprints. The overall exercise to rest ratios for small-sided training games (1:13) were similar to or greater than domestic competition against male youth teams (1:15) and national-league (1:16) and international (1:12) competitions. During the international matches analyzed, 4.8 +/- 2.8 repeated-sprint bouts occurred per player, per match. The number of sprints within the repeated-sprint bouts was 3.4 +/- 0.8. The sprint duration was 2.1 +/- 0.7 seconds, and the recovery time between sprints was 5.8 +/- 4.0 seconds. Most recovery between sprints was active in nature (92.6%). In contrast to international competition, repeated-sprint bouts were uncommon in small-sided training games, domestic competition against male youth teams, and national-league competition. These findings demonstrate that small-sided training games simulate the overall movement patterns of women's soccer competition but offer an insufficient training stimulus to simulate the high-intensity, repeated-sprint demands of international competition.

    http://www.ncbi.nlm.nih.gov/pubmed/18550972

    This is my rationale behind 'soccer is not RSA', but RSA happens in soccer :)

    ReplyDelete
  9. Another interesting

    J Strength Cond Res. 2010 May;24(5):1191-4.
    The development of a test of repeated-sprint ability for elite women's soccer players.
    Gabbett TJ.
    Source

    Brisbane Broncos Rugby League Club, Queensland, Australia. timg@broncos.com.au
    Abstract

    The purpose of this study was to develop a game-specific test of repeated-sprint ability for elite women's soccer players. Nineteen elite women's soccer players (mean +/- SD; age, 18.1 +/- 2.9 y) participated in this study. After familiarization, players completed a repeated-sprint test consisting of 6 x 20-m maximal effort sprints, on a 15-second cycle. At the completion of each sprint, players performed a 10-m deceleration and a 10-m active jog recovery. Ten elite female soccer players performed the test on 2 occasions, 1 week apart, to determine the reliability of the test. In addition, the validity of the repeated-sprint test to discriminate among players of different playing ability was evaluated by testing national (n = 11) and state (n = 8) women's soccer players. Heart rate and blood lactate concentration were recorded to determine the physiological responses to the test. The total sprint time proved to be highly reproducible (intraclass correlation coefficient = 0.91; typical error of measurement = 1.5%). However, the percentage decrement was less reliable (intraclass correlation coefficient = 0.14, typical error of measurement = 19.5%). The repeated-sprint test was valid in discriminating between national- and state-level players, with national players having significantly lower (p < 0.01) total repeated-sprint times than state players (20.9 +/- 0.5 s vs. 23.3 +/- 0.4 s). The mean (+/-SD) heart rate and blood lactate concentration were 182 +/- 6 beats/min and 9.3 +/- 2.0 mmol/L, respectively. The results of this study demonstrate that the developed repeated-sprint test discriminates players of higher and lesser skill levels and offers a reliable method of assessing repeated-sprint ability in elite women's soccer players when results are expressed as the total sprint time.

    http://www.ncbi.nlm.nih.gov/pubmed/20386127

    ReplyDelete