The effects of repeated-sprint training on field-based fitness measures: a meta-analysis of controlled and non-controlled trials

Background: Repeated-sprint training appears to be an efficient and practical means for the simultaneous development of different components of fitness relevant to team sports. Objective: Our objective was to systematically review the literature and meta-analyse the effect of repeated-sprint training on a selection of field-based measures of athletic performance, i.e. counter-movement jump, 10 m sprint, 20 m sprint, 30 m sprint, repeated-sprint ability and high-intensity intermittent running performance. Data Sources: The SPORTDiscus, PubMed, MEDLINE and Web of Science databases were searched for original research articles. Search terms included 'repeated-sprint training', 'sprint training', 'aerobic endurance', 'repeated-sprint ability', 'counter-movement jump' and 'sprint performance'. Study Selection: Inclusion criteria included intervention consisting of a series of ≤10 s sprints with ≤60 s recovery; trained participants; intervention duration of 2–12 weeks; field-based fitness measures; running- or cycling-based intervention; published up to, and including, February 2014. Data Extraction: Our final dataset included six trials for counter-movement jump (two controlled trials), eight trials for 10 m sprint, four trials for 20 m sprint (three controlled trials), two trials for 30 m sprint, eight trials for repeated-sprint ability and three trials for high-intensity intermittent running performance. Analyses were conducted using comprehensive meta-analysis software. Uncertainty in the meta-analysed effect of repeated-sprint training was expressed as 95 % confidence limits (CL), along with the probability that the true value of the effect was trivial, beneficial or harmful. Magnitude-based inferences were based on standardised thresholds for small, moderate and large changes of 0.2, 0.6 and 1.2 standard deviations, respectively. Results: Repeated-sprint training had a likely small beneficial effect in non-controlled counter-movement jump trials (effect size 0.33; 95 % CL ±0.30), with a possibly moderate beneficial effect in controlled trials (0.63; 95 % CL ±0.44). There was a very likely small beneficial effect on 10 m sprint time in non-controlled trials (−0.42; 95 % CL ±0.24), with a possibly moderate beneficial effect on 20 m sprint time in non-controlled (−0.49; 95 % CL ±0.46) and controlled (−0.65; 95 % CL ±0.61) trials. Repeated-sprint training had a possibly large beneficial effect on 30 m sprint performance in non-controlled trials (−1.01; 95 % CL ±0.93), with possibly moderate beneficial effects on repeated-sprint ability (−0.62; 95 % CL ±0.25) and high-intensity intermittent running performance (−0.61; 95 % CL ±0.54). Conclusions: Repeated-sprint training can induce small to large improvements in power, speed, repeated-sprint ability and endurance, and may have relevance for training in team sports

Short-Term Intensified Cycle Training Alters Acute and Chronic Responses of PGC1 Alpha and Cytochrome C Oxidase IV to Exercise in Human Skeletal Muscle

Reduced activation of exercise responsive signalling pathways have been reported in response to acute exercise after training; however little is known about the adaptive responses of the mitochondria. Accordingly, we investigated changes in mitochondrial gene expression and protein abundance in response to the same acute exercise before and after 10-d of intensive cycle training. Nine untrained, healthy participants (mean plus or minus SD; VO2peak 44.1 plus or minus 17.6 ml/kg/min) performed a 60 min bout of cycling exercise at 164 plus or minus 18 W (72% of pre-training VO2peak). Muscle biopsies were obtained from the vastus lateralis muscle at rest, immediately and 3 h after exercise. The participants then underwent 10-d of cycle training which included four high-intensity interval training sessions (6x5 min; 90–100% VO2peak) and six prolonged moderate-intensity sessions (45–90 min; 75% VO2peak). Participants repeated the pre-training exercise trial at the same absolute work load (64% of pre-training VO2peak). Muscle PGC1-alpha mRNA expression was attenuated as it increased by 11- and 4- fold (P<0.001) after exercise pre- and post-training, respectively. PGC1-a protein expression increased 1.5 fold (P<0.05) in response to exercise pre-training with no further increases after the post-training exercise bout. RIP140 protein abundance was responsive to acute exercise only (P<0.01). COXIV mRNA (1.6 fold; P<0.01) and COXIV protein expression (1.5 fold; P<0.05) were increased by training but COXIV protein expression was decreased (20%; P<0.01) by acute exercise pre- and post-training. These findings demonstrate that short-term intensified training promotes increased mitochondrial gene expression and protein abundance. Furthermore, acute indicators of exercise-induced mitochondrial adaptation appear to be blunted in response to exercise at the same absolute intensity following short-term training