The Effects of Sprint Interval Training on Physical Performance: A Systematic Review and Meta-Analysis.

ABSTRACT: Hall, AJ, Aspe, RR, Craig, TP, Kavaliauskas, M, Babraj, J, and Swinton, PA. The effects of sprint interval training on physical performance: a systematic review and meta-analysis. J Strength Cond Res 37(2): 457-481, 2023-The present study aimed to synthesize findings from published research and through meta-analysis quantify the effect of sprint interval training (SIT) and potential moderators on physical performance outcomes (categorized as aerobic, anaerobic, mixed aerobic-anaerobic, or muscular force) with healthy adults, in addition to assessing the methodological quality of included studies and the existence of small study effects. Fifty-five studies were included (50% moderate methodological quality, 42% low methodological quality), with 58% comprising an intervention duration of ≤4 weeks and an array of different training protocols. Bayesian's meta-analysis of standardized mean differences (SMD) identified a medium effect of improved physical performance with SIT (ES 0.5 = 0.52; 95% credible intervals [CrI]: 0.42-0.62). Moderator analyses identified overlap between outcome types with the largest effects estimated for anaerobic outcomes (ES 0.5 = 0.61; 95% CrI: 0.48-0.75). Moderator effects were identified for intervention duration, sprint length, and number of sprints performed per session, with larger effects obtained for greater values of each moderator. A substantive number of very large effect sizes (41 SMDs > 2) were identified with additional evidence of extensive small study effects. This meta-analysis demonstrates that short-term SIT interventions are effective for developing moderate improvements in physical performance outcomes. However, extensive small study effects, likely influenced by researchers analyzing many outcomes, suggest potential overestimation of reported effects. Future research should analyze fewer a priori selected outcomes and investigate models to progress SIT interventions for longer-term performance improvements.

The Impact of Sprint Interval Training Frequency on Blood Glucose Control and Physical Function of Older Adults.

Exercise is a powerful tool for improving health in older adults, but the minimum frequency required is not known. This study sought to determine the effect of training frequency of sprint interval training (SIT) on health and physical function in older adults. Thirty-four (13 males and 21 females) older adults (age 65 ± 4 years) were recruited. Participants were allocated to a control group (CON n = 12) or a once- (n = 11) or twice- (n = 11) weekly sprint interval training (SIT) groups. The control group maintained daily activities; the SIT groups performed 8 weeks of once- or twice-weekly training sessions consisting of 6 s sprints. Metabolic health (oral glucose tolerance test), aerobic capacity (walk test) and physical function (get up and go test, sit to stand test) were determined before and after training. Following training, there were significant improvements in blood glucose control, physical function and aerobic capacity in both training groups compared to control, with changes larger than the smallest worthwhile change. There was a small to moderate effect for blood glucose (d = 0.43-0.80) and physical function (d = 0.43-0.69) and a trivial effect for aerobic capacity (d = 0.01) between the two training frequencies. Once a week training SIT is sufficient to produce health benefits. Therefore, the minimum time and frequency of exercise required is much lower than currently recommended.

Changes in lactate kinetics underpin soccer performance adaptations to cycling-based sprint interval training.

In adolescent soccer, 23% of the distance covers happens at speeds above onset of blood lactate accumulation which suggests that lactate kinetics may be important for soccer performance. We sought to determine the effectiveness of sprint interval training (SIT) on changing performance and lactate kinetics in adolescent soccer players. Thirteen elite soccer academy players (age 15 ± 0.5y) underwent baseline testing (0-10 m and 10-20 m sprint performance, Wingate anaerobic Test (WaNT) with blood lactate measurements and incremental VO2 peak test) before being allocated to control or SIT group. The control group maintained training whilst the HIT group carried out twice-weekly all-out effort cycle sprints consisting of 6 × 10 s sprint with 80 s recovery. There were significant time x group interactions for 10-20 m sprint time (Control pre: 1.32 ± 0.07 s post: 1.35 ± 0.08 s; SIT pre: 1.29 ± 0.04 s post: 1.25 ± 0.04 s; p = 0.01), Peak Power (Control pre: 13.1 ± 1.3 W.kg-1 post: 13.2 ± 1.47 W.kg-1; SIT pre: 12.4 ± 1.3 W.kg-1 post: 15.3 ± 0.7 W.kg-1; p = 0.01) and time to exhaustion (Control pre: 596 ± 62 s post: 562 ± 85 s; SIT pre: 655 ± 54 s post: 688 ± 55 s; p = 0.001). The changes in performance were significantly correlated to changes in lactate kinetics (power: r = 0.55; 10-20 m speed: r = -0.54; time to exhaustion: r = 0.55). Therefore, cycle based SIT is an effective training paradigm for elite adolescent soccer players and the improvements in performance are associated with changes in lactate kinetics.

Early Adaptations to a Two-Week Uphill Run Sprint Interval Training and Cycle Sprint Interval Training.

This study sought to compare early physiological and performance adaptations between a two-week cycle sprint interval training (SIT) and uphill run sprint training (UST) programs. Seventeen recreationally active adult males (age = 28 ± 5 years; body mass (BM) = 78 ± 9 kg) were assigned to either a control (n = 5), SIT (n = 6), or UST (n = 6) group. A discrete group of participants (n = 6, age = 33 ± 6 years, and body mass = 80 ± 9 kg) completed both training protocols to determine acute physiological responses. Intervention groups completed either a run or cycle peak oxygen uptake (VO2peak) test (intervention type dependent) prior to and following two weeks of training. Training comprised of three sessions per week of 4 × 30-s "all-out" sprints with a four-minute active recovery between bouts on a cycle ergometer against 7.5% of body mass in the SIT group and on a 10% slope in the UST group. The VO2peak values remained unchanged in both training groups, but time-to-exhaustion (TTE) was significantly increased only in the UST group (pre-495 ± 40 s, post-551 ± 15 s; p = 0.014) and not in the SIT group (pre-613 ± 130 s, post-634 ± 118 s, p = 0.07). Ventilatory threshold (VT) was significantly increased in both training groups (SIT group: pre-1.94 ± 0.45 L·min-1, post-2.23 ± 0.42 L·min-1; p < 0.005, UST group: pre-2.04 ± 0.40 L·min-1, post-2.33 ± 0.34 L·min-1, p < 0.005). These results indicate that UST may be an effective alternative to SIT in healthy individuals.

Cardiorespiratory fitness and aerobic performance adaptations to a 4-week sprint interval training in young healthy untrained females.

PURPOSE: The aim of this study was to test the effects of sprint interval training (SIT) on cardiorespiratory fitness and aerobic performance measures in young females. METHODS: Eight healthy, untrained females (age 21 ± 1 years; height 165 ± 5 cm; body mass 63 ± 6 kg) completed cycling peak oxygen uptake ([Formula: see text] peak), 10-km cycling time trial (TT) and critical power (CP) tests pre- and post-SIT. SIT protocol included 4 × 30-s "all-out" cycling efforts against 7 % body mass interspersed with 4 min of active recovery performed twice per week for 4 weeks (eight sessions in total). RESULTS: There was no significant difference in [Formula: see text] peak following SIT compared to the control period (control period: 31.7 ± 3.0 ml kg-1 min-1; post-SIT: 30.9 ± 4.5 ml kg-1 min-1; p > 0.05), but SIT significantly improved time to exhaustion (TTE) (control period: 710 ± 101 s; post-SIT: 798 ± 127 s; p = 0.00), 10-km cycling TT (control period: 1055 ± 129 s; post-SIT: 997 ± 110 s; p = 0.004) and CP (control period: 1.8 ± 0.3 W kg-1; post-SIT: 2.3 ± 0.6 W kg-1; p = 0.01). CONCLUSIONS: These results demonstrate that young untrained females are responsive to SIT as measured by TTE, 10-km cycling TT and CP tests. However, eight sessions of SIT over 4 weeks are not enough to provide sufficient training stimulus to increase [Formula: see text] peak.

Effects of in-season uphill sprinting on physical characteristics in semi-professional soccer players.

BACKGROUND: Soccer performance is determined by a number of physiological adaptations that can be altered by high intensity training. However, the effectiveness of using an uphill sprint based protocol has not been demonstrated for soccer players. We sought to determine the effectiveness of an in-season uphill sprint training (UST) programme on soccer related physiological outcomes. METHODS: Fourteen male soccer players (age: 22±8 years, height: 1.81±8 m, body mass: 76±12 kg) underwent testing (5-10-5 agility drill, Yo-Yo Intermittent Recovery Test Level 1, leg and back dynamometry and 3 km time trial) at baseline and after 6 weeks of UST or normal activity. Participants were allocated to a control (N.=7) or UST (N.=7) group. The UST group took part in twice weekly training consisting of 10 x 10 sec sprints with 60s recovery on a 7% gradient for six weeks. The control group maintained normal activity patterns. RESULTS: 3 km time trial, strength, agility and Yo-Yo performance were all significantly improved pre to post following 6 weeks of UST (agility 3%, d=1.3; strength 10%, d=-3.2; VO2max 3%, d=-1.4; 3-km TT 4%, d=1.3). In the control group 3 km time trial, strength, agility and Yo-Yo performance remained unchanged after 6 weeks (agility 0.1%, d=-0.2; strength 2%, d=0.0; VO2max -0.1%, d=0.0; 3-km TT 1.3%, d=0.3). CONCLUSIONS: Therefore in-season short duration UST is an effective way to improve soccer fitness in a time efficient manner.

High-Intensity Cycling Training: The Effect of Work-to-Rest Intervals on Running Performance Measures.

The work-to-rest ratio during cycling-based high-intensity interval training (HIT) could be important in regulating physiological and performance adaptations. We sought to determine the effectiveness of cycling-based HIT with different work-to-rest ratios for long-distance running. Thirty-two long-distance runners (age: 39 ± 8 years; sex: 14 men, 18 women; average weekly running training volume: 25 miles) underwent baseline testing (3-km time-trial, V[Combining Dot Above]O2peak and time to exhaustion, and Wingate test) before a 2-week matched-work cycling HIT of 6 × 10-second sprints with different rest periods (30 seconds [R30], 80 seconds [R80], 120 seconds [R120], or control). Three-kilometer time trial was significantly improved in the R30 group only (3.1 ± 4.0%, p = 0.04), whereas time to exhaustion was significantly increased in the 2 groups with a lower work-to-rest ratio (R30 group 6.4 ± 6.3%, p = 0.003 vs. R80 group 4.4 ± 2.7%, p = 0.03 vs. R120 group 1.9 ± 5.0%, p = 0.2). However, improvements in average power production were significantly greater with a higher work-to-rest ratio (R30 group 0.3 ± 4.1%, p = 0.8 vs. R80 group 4.6 ± 4.2%, p = 0.03 vs. R120 group 5.3 ± 5.9%, p = 0.02), whereas peak power significantly increased only in the R80 group (8.5 ± 8.2%, p = 0.04) but not in the R30 group (4.3 ± 6.1%, p = 0.3) or in the R120 group (7.1 ± 7.9%, p = 0.09). Therefore, cycling-based HIT is an effective way to improve running performance, and the type and magnitude of adaptation is dependent on the work-to-rest ratio.

The Influence of Serial Carbohydrate Mouth Rinsing on Power Output during a Cycle Sprint.

The objective of the study was to investigate the influence of serial administration of a carbohydrate (CHO) mouth rinse on performance, metabolic and perceptual responses during a cycle sprint. Twelve physically active males (mean (± SD) age: 23.1 (3.0) years, height: 1.83 (0.07) m, body mass (BM): 86.3 (13.5) kg) completed the following mouth rinse trials in a randomized, counterbalanced, double-blind fashion; 1. 8 x 5 second rinses with a 25 ml CHO (6% w/v maltodextrin) solution, 2. 8 x 5 second rinses with a 25 ml placebo (PLA) solution. Following mouth rinse administration, participants completed a 30 second sprint on a cycle ergometer against a 0.075 g·kg(-1) BM resistance. Eight participants achieved a greater peak power output (PPO) in the CHO trial, resulting in a significantly greater PPO compared with PLA (13.51 ± 2.19 vs. 13.20 ± 2.14 W·kg(-1), p < 0.05). Magnitude inference analysis reported a likely benefit (81% likelihood) of the CHO mouth rinse on PPO. In the CHO trial, mean power output (MPO) showed a trend for being greater in the first 5 seconds of the sprint and lower for the remainder of the sprint compared with the PLA trial (p > 0.05). No significant between-trials difference was reported for fatigue index, perceived exertion, arousal and nausea levels, or blood lactate and glucose concentrations. Serial administration of a CHO mouth rinse may significantly improve PPO during a cycle sprint. This improvement appears confined to the first 5 seconds of the sprint, and may come at a greater relative cost for the remainder of the sprint. Key pointsThe paper demonstrates that repeated administration of a carbohydrate mouth rinse can significantly improve peak power output during a single 30 second cycle sprint.The ergogenic effect of the carbohydrate mouth rinse may relate to the duration of exposure of the oral cavity to the mouth rinse, and associated greater stimulation of oral carbohydrate receptors.The significant increase in peak power output with the carbohydrate mouth rinse may come at a relative cost for the remainder of the sprint, evidenced by non-significantly lower mean power output and a greater fatigue index in the carbohydrate vs. placebo trial.Serial administration of a carbohydrate mouth rinse may be beneficial for sprint athletes as a method of performance enhancement that minimizes the risk of performance decrement through body mass increase and gastrointestinal disturbances associated with ingesting carbohydrate solutions.