Short‐term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance

Abstract

Brief, intense exercise training may induce metabolic and performance adaptations comparable to traditional endurance training. However, no study has directly compared these diverse training strategies in a standardized manner. We therefore examined changes in exercise capacity and molecular and cellular adaptations in skeletal muscle after low volume sprint-interval training (SIT) and high volume endurance training (ET). Sixteen active men (21 ± 1 years,V O 2 peak = 4.0 ± 0.21 min −1 ) were assigned to a SIT or ET group (n = 8 each) and performed six training sessions over 14 days. Each session consisted of either four to six repeats of 30 s 'all out' cycling at ∼250%V O 2 peak with 4 min recovery (SIT) or 90-120 min continuous cycling at ∼65%V O 2 peak (ET). Training time commitment over 2 weeks was ∼2.5 h for SIT and ∼10.5 h for ET, and total training volume was ∼90% lower for SIT versus ET (∼630 versus ∼6500 kJ). Training decreased the time required to complete 50 and 750 kJ cycling time trials, with no difference between groups (main effects, P ≤ 0.05). Biopsy samples obtained before and after training revealed similar increases in muscle oxidative capacity, as reflected by the maximal activity of cytochrome c oxidase (COX) and COX subunits II and IV protein content (main effects, P ≤ 0.05), but COX II and IV mRNAs were unchanged. Training-induced increases in muscle buffering capacity and glycogen content were also similar between groups (main effects, P ≤ 0.05). Given the large difference in training volume, these data demonstrate that SIT is a time-efficient strategy to induce rapid adaptations in skeletal muscle and exercise performance that are comparable to ET in young active men.

Physiological and molecular responses to an acute bout of reduced-exertion high-intensity interval training (REHIT)

“…This is supported by the recent findings that several markers of oxidative capacity in skeletal muscle, such as citrate synthase and COX IV, as well as protein levels of GLUT4 are increased following a 6-week REHIT intervention . Although such responses have commonly been observed following a variety of submaximal and supramaximal HIT protocols (Gibala et al 2009;Little et al 2011;Little et al 2010;Burgomaster et al 2005;Hood et al 2011;Gibala et al 2006), the current study and that by together suggest that these responses may be achieved with a much smaller volume of exercise than previously thought.…”

“…Given that the majority of glycogenolysis, and hence metabolic acidosis, occurs during the first sprint of a repeated sprint protocol (Parolin et al 1999) it is not surprising that a protocol involving a smaller number of shorter sprints poses a similar challenge to buffering mechanisms compared with more strenuous HIT protocols, and hence still has this effect on RER (Hazell et al 2012;Chan and Burns 2013). It can be speculated that this regular overloading (and recovery) of muscle and blood buffering mechanisms provides an explanation for the adaptations in buffering capacity observed following six weeks of HIT (Gibala et al 2006).…”

“…As 'lack of time' has been identified as one of the main barriers to becoming and remaining physically active (Korkiakangas et al 2009;Reichert et al 2007), over the past decade research has focused on high-intensity interval training (HIT) as a timeefficient alternative to aerobic exercise . Although initial studies have convincingly demonstrated equal or better health benefits with various HIT protocols compared to much larger volumes of aerobic exercise (Gibala et al 2006;Shepherd et al 2013;Cocks et al 2013;Burgomaster et al 2008;Trapp et al 2008;Gillen et al 2013;Little et al 2010), these HIT protocols tend to be very strenuous and as such are unlikely to be adhered to by sedentary populations. Furthermore, most HIT protocols are not as time-efficient as sometimes claimed, with the total time per exercise session generally exceeding 20-30 minutes (Gibala et al 2006;Rakobowchuk et al 2008;Shepherd et al 2013;Cocks et al 2013;Burgomaster et al 2008;Trapp et al 2008;Gillen et al 2013;Little et al 2010).…”

“…Although initial studies have convincingly demonstrated equal or better health benefits with various HIT protocols compared to much larger volumes of aerobic exercise (Gibala et al 2006;Shepherd et al 2013;Cocks et al 2013;Burgomaster et al 2008;Trapp et al 2008;Gillen et al 2013;Little et al 2010), these HIT protocols tend to be very strenuous and as such are unlikely to be adhered to by sedentary populations. Furthermore, most HIT protocols are not as time-efficient as sometimes claimed, with the total time per exercise session generally exceeding 20-30 minutes (Gibala et al 2006;Rakobowchuk et al 2008;Shepherd et al 2013;Cocks et al 2013;Burgomaster et al 2008;Trapp et al 2008;Gillen et al 2013;Little et al 2010). However, more recently we (Metcalfe et al 2012) and others Hazell et al 2010;Tjønna et al 2013) have demonstrated that performing HIT protocols consisting of fewer and/or shorter sprints does not appear to attenuate the associated training adaptations, as long as the exercise intensity remains high.…”

The effect of high-intensity cycling training on postural sway during standing under rested and fatigued conditions in healthy young adults

“…A series of studies have shown that as few as six HIT sessions in 2 weeks increased skeletal muscle oxidative capacity, reflected by the maximal activity and/or protein content of mitochondrial enzymes (Burgomaster et al 2005;2008;Gibala et al 2006;Talanian et al 2007). Low volume HIT may therefore represent a time-efficient strategy to rapidly increase general aerobic fitness which may subsequently contribute to greater safety during activities of daily life and sports-related tasks (Hassanlouei et al 2014).…”