I very much enjoyed reading the ‘warm up’ article by Steven N Blair in the January edition of BJSM. The first study that he quoted on attributable fractions for all cause deaths was a real eye popper!

I was very surprised to see that low cardiorespiratory fitness was a greater attributable risk factor (in both sexes) than obesity, smoking, high cholesterol, and diabetes, as well as hypertension in women.

The second study was almost equally as fascinating. This illustrated that the risk of cardiovascular mortality in Type 2 diabetes in the obese category who took moderate to high levels of exercise, was half that of diabetics in the normal weight category who took no exercise. There was one thing that puzzled me and that was the histograms illustrated that for the type 2 diabetics who took low levels of exercise the cardiovascular risk was the same for those in the obese category as in the normal weight group.

This article will certainly alter the way that I communicate health promotion to my patients, and I would like to congratulate Steven Blair for such a stimulating article.

By Bethany B. Barone and Kerry J. Stewart, Johns Hopkins University

The use of absolute versus weight standardized maximal oxygen consumption during fitness testing has been debated, especially in the context of intervention trials that may induce weight change. We recently showed that exercise training-related changes in exercise systolic blood pressure (SBP) were independently predicted by changes in fatness (by waist circumference) and fitness (by VO2peak in mL/min.kg).

Dr. Shephard correctly points out that reductions in weight could increase VO2peak adjusted for weight without absolute increases in fitness and commented on our use of fitness standardized to weight rather than absolute change in fitness. Though our 6-month exercise-only intervention was associated with minimal weight loss compared to controls (-1.8 kg), we did repeat our analysis using change in absolute fitness to address his concerns.

Our original analysis found that each 1.0 ml/kg.min increase in VO2peak and 1.0 cm decrease in waist circumference independently predicted a 1.0 mm Hg decrease in exercise SBP (p=0.04 and p=0.001, respectively). When we repeated this analysis using maximal absolute oxygen consumption, results were consistent with our original report. A 100 ml/min increase in VO2peak was associated with a 1.1 mm Hg decrease in exercise SBP (p=0.057); a 1.0 cm decrease in waist circumference was associated with a 1.2 mm Hg decrease in exercise SBP (>0.001). Therefore, we affirm our original conclusions that increased fitness has a beneficial effect on exercise SBP beyond weight loss.

“Effects of left- or right-hand preference on the success of boxers in Turkey”, is an interesting and important addition to the research literature on the effect of handedness in sport. However, we believe that the explanation of the cause of the advantage of left- handedness is misleading and needs correction.

Gursoy attributes the superior performance of left-handed boxers to ‘superior spacio-motor skills’ and links this to neurological factors and brain lateralisation. A more prosaic alternative explanation is not mentioned, namely a frequency-dependent advantage accruing to the individuals of the minority disposition simply by virtue of their minority status1,2 . Consider a right-hander competing against a left-hander: the right-hander has had less experience facing left-handers than his opponent has had facing right-handers. The left-hander is therefore at an advantage.

Support for this interpretation is provided by the observation that the advantage accruing to left-handers does not appear to extend to ‘non- interactive’ sports, where opponents compete separately and in sequence 3,4 . For example, no advantage appears to operate among darts players or ten-pin bowlers 5 . In these sports, a competitor’s unfamiliar handedness is unlikely to have an effect on the performance of his opponents. However, ‘superior spacio-motor skills’ of the sort implicated by Gursoy as underlying the effects observed would presumably still be of value.

The results of Gursoy’s paper are particularly interesting from an evolutionary perspective. A frequency-dependent advantage accruing to left -handed individuals in male-male combat has been hypothesised to explain the evolution of a balanced polymorphism of handedness during human evolutionary history 6,7 . Although the apparent advantage accruing to left-handedness in combat has been observed by fencing masters as early as the sixteenth century 8 , to our knowledge Gursoy’s paper is the first to rigorously demonstrate an advantage in combat and adds empirical support to this theory.

1 Wood CJ, and Aggleton JP. Handedness in ‘fast ball’ sports: do left -handers have an innate advantage? Br J Psychol. 1989; 80(2):227-40

2 Brooks R, Bussiere L, Jennions MD, Hunt J. Sinister strategies succeed at the Cricket World Cup. Proceedings of the Royal Society Series B (Biology Letters, Supplement) 2003 271: S64-S66

3 Raymond M, Pontier D, Dufour A and Møller AP. Frequency-dependent maintenance of left-handedness in humans Proc R Soc Lond B 1996 263: 1627- 1633

4 Grouios G, Tsorbatzoudis H, Alexandris K and Barkoukis V. Do left- handed competitors have an innate superiority in sports? Percept Mot Skills 2000 3(2): 1273-822000

5 Aggleton, J. P. & Wood, C. J. Is there a left-handed advantage in ‘ballistic’ sports? International Journal of Sport Psychology, 1990, 21, 46-57.

6 Billiard S, Faurie C and Raymond M. Maintenance of handedness polymorphism in humans: a frequency-dependent selection model Journal of Theoretical Biology 235(1), 7 July 2005, Pages 85-93 2005

7 Faurie C and Raymond M Handedness, homicide and negative frequency- dependent selection Proc. R. Soc. B (2005) 272, 25–28

8 Harris, Lauren Julius (2007). In fencing, what gives left-handers the edge? Views from the present and the distant past. Laterality: Asymmetries of Body, Brain and Cognition, 99999 (1), 1-41. Retrieved February 24, 2009, from http://www.informaworld.com/10.1080/13576500701650430

By May Arna Risberg, Havard Moksnes, Annika Storevold, Inger Holm, and Lynn Snyder-Mackler

I work in the rehab field by 18 years with a direct experience of ACL rehabs of more than 600 cases. It’s absolutely normal that after 60 days people can’t jump like before surgery. In my experience, I use testing ACL patients, first time, after 90 days from surgery for side to side impairment with isokinetic, electronic balance board and jump test with optic fiber. Often in the first two tests we find an average good balance.It’s not the same for the jump test. Usually we start dynamic rehab later for post surgery purposes.

That’s the reason because after 60 days is very difficult to have a complete recovery, even in a functional movement like the jump. And that’s the reason because is very difficult come back to competition before than four months, especially in the pivot-shift sports.

Kind regards,
Fulvio Stradijot