The present study was proposed to study effects of both handball training program followed by tapering period on plasma miRNA-1 & 206 and on progress of handball skills after eight successive weeks followed by five days of tapering.
Discussing the purpose of this study was to assess the effects of the alterations of taper components on performance in handball athletes. In accordance with previous suggestions (Bosquet et al., 2007), it is found that maximal gains are obtained with a tapering intervention of five days duration, where the training volume is exponentially decreased by about 20%, without any modification of training regularity. In agreement with previous suggestions (28,46), this study has confirmed that performance improvement was sensitive to the reduction in training volume. Maximal performance gains are obtained with a total reduction in training volume of 41–60% of pre-taper value. Training volume can be altered through the decrease of the duration of each training session and/or the decrease of training frequency.
(49) From a neuromuscular perspective, the taper usually results in markedly increased muscular strength and power, often associated with performance gains at the muscular and whole body level. Oxidative enzyme activities can increase, along with positive changes in single muscle fiber size, metabolic properties and contractile properties. Limited research on the influence of the taper on athletes’ immune status indicates that small changes in immune cells, immunoglobulins and cytokines are unlikely to compromise overall immunological protection.
The pre-event taper may also be characterized by psychological changes in the athlete, including a reduction in total mood disturbance and somatic complaints, improved somatic relaxation and self-assessed physical conditioning scores, reduced perception of effort and improved quality of sleep. These changes are often associated with improved post-taper performances expressed in this study.
Mujika , 2010 suggested that training at high intensities before the taper plays a key role in inducing maximal physiological and performance adaptations in both moderately trained subjects and highly trained athletes. High-intensity training can also maintain or further enhance training-induced adaptations while athletes reduce their training before a major competition. On the other hand, training volume can be markedly reduced without a negative impact on athletes’ performance. Therefore, the training load should not be reduced at the expense of intensity during the taper. Intense exercise is often a performance-determining factor during match play in team sports, and high-intensity training can also elicit major fitness gains in team sport athletes. A tapering and peaking program before the start of a league format championship or a major tournament should be characterized by high-intensity activities.
Results of this study revealed significant effect of tapering on plasma miRNA 1 & 206 which is the first to be obtained in athletes. Hence, it is a pioneer study to prove why tapering increase athlete performance empirically on the basis of molecular biology.
Following an acute bout of resistance exercise, performed by both young and older men, pri-miR-1 and pri-miR-133a were reduced in muscle biopsy samples taken from the young subjects 6 h post exercise (Drummond et al. 2008). In contrast, pri-miR-206 was increased at 3 and 6 h post exercise in the older and young subjects, respectively (Drummond et al. 2008). Of the mature miRNAs, only miR-1 was reduced at 3 and 6 h post exercise in the older and young subjects, respectively; no changes in miR-206 were observed.
Following functional overload-induced hypertrophy, primary miR-1, and -206 are increased. In contrast, the mature forms of miR-1 are decreased while miR-206 is unchanged. There is also an increase in several growth-related genes that are predicted targets of these miRNAs (Guller and Russell, 2010). An injection of a cocktail of miRNAs including miR-1, -133 and -206 into injured muscle site enhanced muscle regeneration and prevented fibrosis (Nakasa et al. 2009). These results suggested a role of miR-1, and -206 in tissue repair after acute exercise training sessions and probably participate in tissue enhanced performance at tapering periods.
RNA interference (RNAi) is a natural process that cells use to turn down the activity of specific genes. In conjunction with this, MiRNAs, or microRNAs, are endogenous triggers of RNAi which have been shown to have essential roles in developmental processes including in skeletal muscle Sibley and Wood, 2011; Mishra and Bertino, 2009. A key feature of the RNAi and miRNA mechanism is sequence specificity.
These studies show that exercise is capable of regulating miRNA levels. It will be important to identify which exercise-induced pathways alter miRNA expression and how miRNA regulation contributes to the physiological adaptations to exercise. Investigations that identify the miRNAs responsible for exercise-induced adaptations, or which can mimic some exercise-induced adaptations, will significantly advance the miRNA–muscle field.
At the end, some questions are arising from this study although they were not included in the intellectual consideration at the beginning. First, miRNAs are small, non coding RNAs that they can be synthesized in vitro so easy. Hence, they can be used as doping before further investigation required for safety. Do athletes will wait? Second, they are highly metabolized, and then if they are used as doping, they will be discovered? Also, Are Scientists will administrate miRNAs to embryos to get genetically assessed babies? This means many studies are required in this field to answer such questions.