Lanferdini Fábio J, Krüger Renata L, Baroni Bruno M, Lazzari Caetano, Figueiredo Pedro, Reischak-Oliveira Alvaro, Vaz Marco A
Laboratório de Pesquisa do Exercício, Escola de Educação Física, Fisioterapia e Dança, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
Universidade Regional Integrada do Alto Uruguai e das Missões, Santo Ângelo, RS, Brazil.
Lasers Med Sci. 2018 Apr;33(3):453-460. doi: 10.1007/s10103-017-2347-y. Epub 2017 Nov 9.
Some evidence supports that low-level laser therapy (LLLT) reduces neuromuscular fatigue, so incrementing sports performance. A previous randomized controlled trial of our group showed increased exercise tolerance in male competitive cyclists treated with three different LLLT doses (3, 6, and 9 J/diode; or 135, 270, and 405 J/thigh) before time-to-exhaustion cycling tests. Now, the present study was designed to evaluate the effects of these LLLT doses on the VO kinetics of athletes during cycling tests. Twenty male competitive cyclists (29 years) participated in a crossover, randomized, double-blind, and placebo-controlled trial. On the first day, the participants performed an incremental cycling test to exhaustion to determine maximal oxygen uptake (VO) and maximal power output (PO), as well as a familiarization with the time-to-exhaustion test. In the following days (2 to 5), all participants performed time-to-exhaustion tests at PO. Before the exhaustion test, different doses of LLLT (3, 6, and 9 J/diode; or 135, 270, and 405 J/thigh, respectively) or placebo were applied bilaterally to the quadriceps muscle. All exhaustion tests were monitored online by an open-circuit spirometry system in order to analyze the VO amplitude, VO delay time, time constant (tau), and O deficit. Tau and O deficit were decreased with LLLT applications compared to the placebo condition (p < 0.05). No differences (p > 0.05) were found between the experimental conditions for VO amplitude and VO delay time. In conclusion, LLLT decreases tau and O deficit during time-to-exhaustion tests in competitive cyclists, and these changes in VO kinetics response can be one of the possible mechanisms to explain the ergogenic effect induced by LLLT.
一些证据支持低强度激光疗法（LLLT）可减轻神经肌肉疲劳，从而提高运动表现。我们团队之前的一项随机对照试验表明，在进行力竭骑行测试前，对男性职业自行车运动员使用三种不同剂量的LLLT（3、6和9焦耳/二极管；或135、270和405焦耳/大腿）进行治疗，可提高运动耐力。现在，本研究旨在评估这些LLLT剂量对运动员在骑行测试中VO动力学的影响。20名男性职业自行车运动员（29岁）参与了一项交叉、随机、双盲和安慰剂对照试验。第一天，参与者进行递增式力竭骑行测试，以确定最大摄氧量（VO）和最大功率输出（PO），并熟悉力竭测试。在接下来的几天（第2至5天），所有参与者在PO下进行力竭测试。在力竭测试前，分别对双侧股四头肌施加不同剂量的LLLT（3、6和9焦耳/二极管；或135、270和405焦耳/大腿）或安慰剂。所有力竭测试均通过开路肺量计系统进行在线监测，以分析VO幅度、VO延迟时间、时间常数（tau）和O亏欠。与安慰剂组相比，LLLT治疗可降低tau和O亏欠（p<0.05）。在VO幅度和VO延迟时间的实验条件之间未发现差异（p>0.05）。总之，LLLT可降低职业自行车运动员在力竭测试期间的tau和O亏欠，VO动力学反应的这些变化可能是解释LLLT诱导的促力效应的可能机制之一。
