Limits...
On the implications of a sex difference in the reaction times of sprinters at the Beijing Olympics.

Lipps DB, Galecki AT, Ashton-Miller JA - PLoS ONE (2011)

Bottom Line: The mean fastest reaction time recorded by men was significantly faster than women (p<0.001).At the 99.9% confidence level, neither men nor women can react in 100 ms, but they can react in as little as 109 ms and 121 ms, respectively.We estimate that female sprinters would have similar reaction times to male sprinters if the force threshold used at Beijing was lowered by 22% in order to account for their lesser muscle strength.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America.

ABSTRACT
Elite sprinters offer insights into the fastest whole body auditory reaction times. When, however, is a reaction so fast that it represents a false start? Currently, a false start is awarded if an athlete increases the force on their starting block above a given threshold before 100 ms has elapsed after the starting gun. To test the hypothesis that the fastest valid reaction times of sprinters really is 100 ms and that no sex difference exists in that time, we analyzed the fastest reaction times achieved by each of the 425 male and female sprinters who competed at the 2008 Beijing Olympics. After power transformation of the skewed data, a fixed effects ANOVA was used to analyze the effects of sex, race, round and lane position. The lower bounds of the 95, 99 and 99.9% confidence intervals were then calculated and back transformed. The mean fastest reaction time recorded by men was significantly faster than women (p<0.001). At the 99.9% confidence level, neither men nor women can react in 100 ms, but they can react in as little as 109 ms and 121 ms, respectively. However, that sex difference in reaction time is likely an artifact caused by using the same force threshold in women as men, and it permits a woman to false start by up to 21 ms without penalty. We estimate that female sprinters would have similar reaction times to male sprinters if the force threshold used at Beijing was lowered by 22% in order to account for their lesser muscle strength.

Show MeSH

Related in: MedlinePlus

Sex difference in rapid plantarflexion moment development.At time (T1) the moments produced by men (Mm) and women (Mf) are indicated by points a and b, respectively. The times taken by men (T1) and women (T2) to develop the plantarflexion moment, Mm, are indicated by points a and c, respectively. Figure is redrawn from [9].
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3198384&req=5

pone-0026141-g002: Sex difference in rapid plantarflexion moment development.At time (T1) the moments produced by men (Mm) and women (Mf) are indicated by points a and b, respectively. The times taken by men (T1) and women (T2) to develop the plantarflexion moment, Mm, are indicated by points a and c, respectively. Figure is redrawn from [9].

Mentions: The increase in propulsive force on the starting blocks is primarily developed by rapid bilateral increases in ankle plantarflexion moment and secondarily by hip extension moments [4], [16]; neither knee contributes much in this regard [16]. When the plantarflexors contract, the reaction force on the foot from the starting block is approximately proportional to the plantarflexion moment divided by the lever arm of that force about the center of the ankle joint. For a given plantarflexion moment, the force developed by healthy young females will be 11% larger than healthy young males due to their smaller foot lever arms [17] (Text S1). However healthy young men, on average, develop 20% greater plantarflexion moment than young women do in the same amount of time (c.f., points ‘a’ and ‘b’ in Fig. 2, [12]). Therefore, healthy young men would develop an 6% larger force on the starting blocks than would healthy young women in the same time interval, T1 (Fig. 2 and Text S1). These calculations would likely change for sprinters given that they are stronger and develop force at a faster rate than healthy young adult non-sprinters [18], [19].


On the implications of a sex difference in the reaction times of sprinters at the Beijing Olympics.

Lipps DB, Galecki AT, Ashton-Miller JA - PLoS ONE (2011)

Sex difference in rapid plantarflexion moment development.At time (T1) the moments produced by men (Mm) and women (Mf) are indicated by points a and b, respectively. The times taken by men (T1) and women (T2) to develop the plantarflexion moment, Mm, are indicated by points a and c, respectively. Figure is redrawn from [9].
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3198384&req=5

pone-0026141-g002: Sex difference in rapid plantarflexion moment development.At time (T1) the moments produced by men (Mm) and women (Mf) are indicated by points a and b, respectively. The times taken by men (T1) and women (T2) to develop the plantarflexion moment, Mm, are indicated by points a and c, respectively. Figure is redrawn from [9].
Mentions: The increase in propulsive force on the starting blocks is primarily developed by rapid bilateral increases in ankle plantarflexion moment and secondarily by hip extension moments [4], [16]; neither knee contributes much in this regard [16]. When the plantarflexors contract, the reaction force on the foot from the starting block is approximately proportional to the plantarflexion moment divided by the lever arm of that force about the center of the ankle joint. For a given plantarflexion moment, the force developed by healthy young females will be 11% larger than healthy young males due to their smaller foot lever arms [17] (Text S1). However healthy young men, on average, develop 20% greater plantarflexion moment than young women do in the same amount of time (c.f., points ‘a’ and ‘b’ in Fig. 2, [12]). Therefore, healthy young men would develop an 6% larger force on the starting blocks than would healthy young women in the same time interval, T1 (Fig. 2 and Text S1). These calculations would likely change for sprinters given that they are stronger and develop force at a faster rate than healthy young adult non-sprinters [18], [19].

Bottom Line: The mean fastest reaction time recorded by men was significantly faster than women (p<0.001).At the 99.9% confidence level, neither men nor women can react in 100 ms, but they can react in as little as 109 ms and 121 ms, respectively.We estimate that female sprinters would have similar reaction times to male sprinters if the force threshold used at Beijing was lowered by 22% in order to account for their lesser muscle strength.

View Article: PubMed Central - PubMed

Affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America.

ABSTRACT
Elite sprinters offer insights into the fastest whole body auditory reaction times. When, however, is a reaction so fast that it represents a false start? Currently, a false start is awarded if an athlete increases the force on their starting block above a given threshold before 100 ms has elapsed after the starting gun. To test the hypothesis that the fastest valid reaction times of sprinters really is 100 ms and that no sex difference exists in that time, we analyzed the fastest reaction times achieved by each of the 425 male and female sprinters who competed at the 2008 Beijing Olympics. After power transformation of the skewed data, a fixed effects ANOVA was used to analyze the effects of sex, race, round and lane position. The lower bounds of the 95, 99 and 99.9% confidence intervals were then calculated and back transformed. The mean fastest reaction time recorded by men was significantly faster than women (p<0.001). At the 99.9% confidence level, neither men nor women can react in 100 ms, but they can react in as little as 109 ms and 121 ms, respectively. However, that sex difference in reaction time is likely an artifact caused by using the same force threshold in women as men, and it permits a woman to false start by up to 21 ms without penalty. We estimate that female sprinters would have similar reaction times to male sprinters if the force threshold used at Beijing was lowered by 22% in order to account for their lesser muscle strength.

Show MeSH
Related in: MedlinePlus