Repeated Sprint Training
Repeated sprint training (RST) has emerged as a popular method used with field-based sports to improve various physiological and physical attributes associated with performance (Girard et al., 2011). Research is historically based around improving anaerobic capacity, generated power and force production (Taylor et al., 2015). However, more recently enhanced aerobic capacity has been presented along with potential mitigation of fatigue (Thurlow, Weakley, et al., 2023). RST involves a maximal bout of effort within a short duration, under ten seconds, with a distinct recovery period lasting a minimum of sixty seconds (Girard et al., 2011). Performed in a straight line over 10-40m with defined sets and repetitions, the use of RST provides exposures to the different phases of running (Turner & Bishop, 2022).
One of the benefits of RST documented is the enhancement of anaerobic capacity (Turner & Bishop, 2022). Research supports this claim, highlighting improvements in sprint performance and high-intensity exercise capacity following a period of RST (Charron et al., 2020). By subjecting the muscles to repeated bouts of intense exercise, RST triggers certain adaptations, such as increased muscle glycogen storage and improved lactate clearance, leading to better anaerobic energy production (Bishop et al., 2011). Reported studies demonstrate an increased muscle fibre cross-sectional area (CSA) and higher maximal voluntary contraction force after RST (Ross & Leveritt, 2001). These adaptations enhance the ability to generate explosive movements, such as accelerating, jumping, and changing direction (Girard et al., 2011).
While much of the focus has been on the effects of repeated sprint training on anaerobic performance, there is growing evidence to suggest that this type of training can also have a positive impact on aerobic performance (Boullosa et al., 2022). This type of training places a significant demand on both the anaerobic and aerobic energy systems, leading to several physiological adaptations that can maintaining or even improving aerobic performance, thus improving overall athletic performance. This is mainly driven from an increase in peak maximum aerobic capabilities (V02max). This is turn gives an increase in V02max capacities, theoretically allowing the athlete to work harder for longer (Boullosa et al., 2022). Two main adaptations occur for this increased performance outcome, increases in both mitochondrial density and capillarisation within muscle tissue (Boullosa et al., 2022).
Previous studies have reported significant V02max improvements through sustained and consistent RST (Taylor et al., 2015 & Gibala et al., 2006). The range of these increases are between 4 to 13.5% when measured during an incremental exhaustive testing battery (Taylor et al., 2015). The recommendation of a 4–8-week RST protocol was sufficient to induce a positive effect on both recreational and well trained field based athletes (Taylor et al., 2015).
The adaptations that occur as a result of repeated sprint training can lead to significant improvements in aerobic performance. Studies have shown that athletes who incorporate repeated sprint training into their training programs experience increases in VO2 max, which is a measure of the maximum amount of oxygen that an individual can utilize during exercise. This increase in VO2 max can lead to improvements in aerobic capacity and endurance, as well as faster recovery between high-intensity efforts. However, there is no consensus on the duration of training for these adaptations to take place. Astorino et al (2011) suggest a minimum of 2 weeks of minimal, 2 to 3 times per week, training to have an effect. This study was with recreational field-based athletes with varying demographics and training age. Other studies have suggested a more appropriate time frame of 4 to 8 weeks with a 3 times per week training protocol (Taylor et al., 2016).
While the benefits highlight the efficacy of RST, it is essential to acknowledge certain limitations and considerations associated. Firstly, the training volume and intensity need to be carefully monitored to avoid injuries, as the repetitive nature of RST places increased stress on the musculoskeletal system (Turner & Bishop, 2022). Sprinting is reported as the highest mechanism of injury to the hamstring muscle group (Malone et al., 2018). Secondly, individual player characteristics and specificity of training must be considered to ensure optimal adaptations. The periodisation and integration of RST with other training components should be carefully planned to prevent counterproductive responses (Turner & Bishop, 2022).
RST from the presented literature and evidence can give a false pretence of a one stop shop for athletes overall performance needs and should be used with caution, pragmatism and consistent review. When considering an increase in intensity, high speed running, very high-speed running and sprint volume during training this could add to the potential injury risk factors (Ekstrand et al., 2023). Monitoring maximum effort and high intensity workload is vital for adequate adaptation and injury prevention (Ekstrand et al., 2023). Weekly increases in sprint distance, termed spikes put the athlete at unnecessary and available risk of soft tissue injury. Literature has tried to define training load spikes but there are differing opinions (Gabbett., 2016). A consensus of weekly increases of 10 to 20% seem to be consistent (Gabbett., 2016). With some researchers being more conservative with a maximum of 10% and others more lenient of 30% (Gabbett., 2016).
It would seem sensible when planning and implementing a RST protocols into the training week that one of two if not both the following approaches were taken. If RST is a new stimulus to the training schedule a slower approach be adopted, low volume with a recommended 10% increment when intensification and progression is used. On the other hand, if RST is the norm a more initialised approach whereby individuals are identified for risk based off age and previous injury history. In this case, the high-risk individuals are started on a low volume low (10%) progressive program. Differing from the low-risk individuals that would start on a high volume with a 20% intensification program. Bianchi et al (2023), stated that a slow increment of sprint by 10% after the third week was both physiological progressive, easily monitored and maintainable during an already busy training schedule which took minimum time.
