Institute of Sports and Sports Science, University of Kassel, Kassel, Germany.
PLoS One. 2012;7(11):e49325. doi: 10.1371/journal.pone.0049325. Epub 2012 Nov 7.
Negative frequency-dependent effects rather than innate predispositions may provide left-handers with an advantage in one-on-one fighting situations. Support mainly comes from cross-sectional studies which found significantly enhanced left-hander frequencies among elite athletes exclusively in interactive sports such as baseball, cricket, fencing and tennis. Since professional athletes' training regimes continuously improve, however, an important unsolved question is whether the left-handers' advantage in individual sports like tennis persists over time. To this end, we longitudinally tracked left-hander frequencies in year-end world rankings (men: 1973-2011, ladies: 1975-2011) and at Grand Slam tournaments (1968-2011) in male and female tennis professionals. Here we show that the positive impact of left-handed performance on high achievement in elite tennis was moderate and decreased in male professionals over time and was almost absent in female professionals. For both sexes, left-hander frequencies among year-end top 10 players linearly decreased over the period considered. Moreover, left-handedness was, however, no longer seems associated with higher probability of attaining high year-end world ranking position in male professionals. In contrast, cross-sectional data on left-hander frequencies in male and female amateur players suggest that a left-handers' advantage may still occur on lower performance levels. Collectively, our data is in accordance with the frequency-dependent hypothesis since reduced experience with left-handers in tennis is likely to be compensated by players' professionalism.
负频率依赖性效应而非先天倾向可能为左撇子在一对一的战斗情况下提供优势。这种支持主要来自于横断面研究，这些研究发现，在棒球、板球、击剑和网球等互动性运动中，精英运动员中左撇子的频率显著增加。然而，由于职业运动员的训练计划不断改进，一个重要的未解决的问题是，在网球等个人运动中，左撇子的优势是否会随着时间的推移而持续存在。为此，我们对男女网球职业运动员年终世界排名（男子：1973-2011 年，女子：1975-2011 年）和大满贯赛事（1968-2011 年）中的左撇子频率进行了纵向跟踪。结果表明，左撇子在精英网球中取得优异成绩的积极影响是适度的，并且随着时间的推移，男性职业运动员的影响逐渐减弱，在女性职业运动员中几乎不存在。对于两性而言，年终前 10 名球员中的左撇子频率在考虑的时间段内呈线性下降。此外，在男性职业运动员中，左撇子似乎不再与获得高年终世界排名的可能性相关。相比之下，关于男性和女性业余运动员中左撇子频率的横断面数据表明，在较低的运动水平上，左撇子可能仍具有优势。总的来说，我们的数据符合频率依赖性假设，因为在网球中，左撇子的经验减少可能会被球员的专业性所弥补。
