Role of active and passive recovery in adaptations to high intensity training

It has been established that Wingate-based high-intensity training (HIT) consisting of 4 to 6 x 30-s all-out sprints interspersed with 4-min recovery is an effective training paradigm. Despite the increased utilisation of Wingate-based HIT to bring about training adaptations, the majority of previous studies have been conducted over a relatively short timeframe (2 to 6 weeks). However, activity during recovery period, intervention duration or sprint length have been overlooked. In study 1, the dose response of recovery intensity on performance during typical Wingate-based HIT (4 x 30-s cycle all-out sprints separated by 4-min recovery) was examined and active recovery (cycling at 20 to 40% of V̇O2peak) has been shown to improve sprint performance with successive sprints by 6 to 12% compared to passive recovery (remained still), while increasing aerobic contribution to sprint performance by ~15%. In the following study, 5 to 7% greater endurance performance adaptations were achieved with active recovery (40%V̇O2peak) following 2 weeks of Wingate-based HIT. In the final study, shorter sprint protocol (4 to 6 x 15-s sprints interspersed with 2 min of recovery) has been shown to be as effective as typical 30-s Wingate-based HIT in improving cardiorespiratory function and endurance performance over 9 weeks with the improvements in V̇O2peak being completed within 3 weeks, whereas exercise capacity (time to exhaustion) being increased throughout 9 weeks. In conclusion, the studies demonstrate that active recovery at 40% V̇O2peak significantly enhances endurance adaptations to HIT. Further, the duration of the sprint does not seem to be a driving factor in the magnitude of change with 15 sec sprints providing similar adaptations to 30 sec sprints. Taken together, this suggests that the arrangement of recovery mode should be considered to ensure maximal adaptation to HIT, and the practicality of the training would be enhanced via the reduction in sprint duration without diminishing overall training adaptations.

Individual Variation in VO2peak Response Following Sprint Interval Training: The Role of Peripheral Adaptation

There is a large degree of heterogeneity in response to regular physical activity at the individual level, with some exhibiting no or very small improvements in VO2peak following highly controlled exercise training. The purpose of this thesis was to examine individual variation in VO2peak response to sprint interval training (SIT) in relation to individual responses to multiple measures of peripheral physiological adaptation. Specifically, VO2peak, capillary density, fibre-specific SDH content, and type I fibre % were measured in 23 young, healthy, recreationally active males before and after 4 weeks SIT (Tabata protocol 4 x per week). The key findings of this experiment included that, when separated into tertiles of VO2peak response, the high (HI) and low (LO) groups differed significantly in VO2peak change after training. Secondly, there was no difference between HI and LO groups for response in any of capillary density, fibre-specific SDH content, or fibre type %, with no correlation found between individual VO2peak response and changes in any measured peripheral variable. Together, these results confirm that individuals respond heterogeneously to SIT and suggest that this heterogeneity does not result from differences in individual changes in capillary density, fibre-specific SDH content or type I fibre %. It is speculated that some other combination of peripheral physiological adaptation must explain variability in VO2peak response to 4 weeks of SIT.

A Group-Enhanced Sprint Interval Training Program for Amateur Athletes

Sprint interval training (SIT) can elicit improvements in aerobic and anaerobic capacity. While variations in SIT protocols have been investigated, the influence of social processes cannot be overlooked. As research supports the use of groups to influence individual cognitions and behaviours, the current project assessed the effectiveness of a group-based intervention with participants conducting SIT. Specifically, 53 amateur athletes (age, 21.9 ± 2.9 years; 53% females) took part in a 4-week training program (3 sessions per week, 30-s “all-out” efforts with 4 min active recovery, repeated 4–6 times per session), and were assigned to “true group”, aggregate, or individual conditions. Results indicated no significant differences between groups for the physiological measures. With regards to training improvements from baseline for all participants— regardless of condition — significant main effects for time were identified for maximal oxygen uptake (2.5–2.8 mL·kg−1·min−1, p < 0.001, η2 = 0.03), time-trial performance (14–32 s, p < 0.001, η2 = 0.37), and anaerobic power (1.1–1.7 k·h−1, p < 0.001, η2 = 0.66). With regards to the psychological measures, significant main effects between groups were found for motivation (p = 0.033, η2 = 0.13), task self-efficacy (p = 0.018, η2 = 0.15), and scheduling self-efficacy (p = 0.003, η2 = 0.22). The true group experienced greater improvements in motivation than the individual condition, but the aggregate and individual conditions demonstrated greater increases in task and scheduling self-efficacy. Though the SIT paradigm employed induced training improvements similar to previous work, the group intervention was not able to further these improvements

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 ( V˙O2V˙O2 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 V˙O2V˙O2 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 V˙O2V˙O2 peak.

The Scientific Basis for High-Intensity Interval Training: Optimising Training Programmes and Maximising Performance in Highly Trained Endurance Athletes

While the physiological adaptations that occur following endurance training in previously sedentary and recreationally active individuals are relatively well understood, the adaptations to training in already highly trained endurance athletes remain unclear. While significant improvements in endurance performance and corresponding physiological markers are evident following submaximal endurance training in sedentary and recreationally active groups, an additional increase in submaximal training (i.e. volume) in highly trained individuals does not appear to further enhance either endurance performance or associated physiological variables [e.g. peak oxygen uptake (V-dot O2peak), oxidative enzyme activity]. It seems that, for athletes who are already trained, improvements in endurance performance can be achieved only through high-intensity interval training (HIT). The limited research which has examined changes in muscle enzyme activity in highly trained athletes, following HIT, has revealed no change in oxidative or glycolytic enzyme activity, despite significant improvements in endurance performance (p < 0.05). Instead, an increase in skeletal muscle buffering capacity may be one mechanism responsible for an improvement in endurance performance. Changes in plasma volume, stroke volume, as well as muscle cation pumps, myoglobin, capillary density and fibre type characteristics have yet to be investigated in response to HIT with the highly trained athlete. Information relating to HIT programme optimisation in endurance athletes is also very sparse. Preliminary work using the velocity at which V-dot O2max is achieved (Vmax) as the interval intensity, and fractions (50 to 75%) of the time to exhaustion at Vmax (Tmax) as the interval duration has been successful in eliciting improvements in performance in long-distance runners. However, Vmax and Tmax have not been used with cyclists. Instead, HIT programme optimisation research in cyclists has revealed that repeated supramaximal sprinting may be equally effective as more traditional HIT programmes for eliciting improvements in endurance performance. Further examination of the biochemical and physiological adaptations which accompany different HIT programmes, as well as investigation into the optimal HIT programme for eliciting performance enhancements in highly trained athletes is required.

Similar health benefits of endurance and high-intensity interval training in obese children

Purpose: To compare two modalities of exercise training (i.e., Endurance Training [ET] and High-Intensity Interval Training [HIT]) on health-related parameters in obese children aged between 8 and 12 years. Methods: Thirty obese children were randomly allocated into either the ET or HIT group. The ET group performed a 30 to 60-minute continuous exercise at 80% of the peak heart rate (HR). The HIT group training performed 3 to 6 sets of 60-s sprint at 100% of the peak velocity interspersed by a 3-min active recovery period at 50% of the exercise velocity. HIT sessions last similar to 70% less than ET sessions. At baseline and after 12 weeks of intervention, aerobic fitness, body composition and metabolic parameters were assessed. Results: Both the absolute (ET: 26.0%; HIT: 19.0%) and the relative VO2 peak (ET: 13.1%; HIT: 14.6%) were significantly increased in both groups after the intervention. Additionally, the total time of exercise (ET: 19.5%; HIT: 16.4%) and the peak velocity during the maximal graded cardiorespiratory test (ET: 16.9%; HIT: 13.4%) were significantly improved across interventions. Insulinemia (ET: 29.4%; HIT: 30.5%) and HOMA-index (ET: 42.8%; HIT: 37.0%) were significantly lower for both groups at POST when compared to PRE. Body mass was significantly reduced in the HIT (2.6%), but not in the ET group (1.2%). A significant reduction in BMI was observed for both groups after the intervention (ET: 3.0%; HIT: 5.0%). The responsiveness analysis revealed a very similar pattern of the most responsive variables among groups. Conclusion: HIT and ET were equally effective in improving important health related parameters in obese youth.

Acute high-intensity interval training improves T-vent and peak power output in highly trained males.

This study examined the effects of four high-intensity interval-training (HIT) sessions performed over 2 weeks on peak volume of oxygen uptake (VO2peak), the first and second ventilatory thresholds (UT VT2) and peak power output (PPO) in highly trained cyclists. Fourteen highly trained male cyclists (VO2peak = 67.5 +/- 3.7 ml . kg(-1) . min(-1)) performed a ramped cycle test to determine VO2peak VT1 VT2, and PPO. Subjects were divided equally into a HIT group and a control group. The HIT group performed four HIT sessions (20 x 60 s at PPO, 120 s recovery); the V-02peak test was repeated <I wk after the HIT program. Control subjects maintained their regular training program and were reassessed under the same timeline. There was no change in V0(2peak) for either group; however, the HIT group showed a significantly greater increase in VT1, (+22% vs. -3%), VT2 (+15% vs. -1%), and PPO (+4.3 vs. -.4%) compared to controls (all P <.05). This study has demonstrated that HIT can improve VT1, VT2,, and PPO, following only four HIT sessions in already highly trained cyclists.

Effects of high-intensity aerobic interval training vs. moderate exercise on hemodynamic, metabolic and neuro-humoral abnormalities of young normotensive women at high familial risk for hypertension

Exercise training has an important role in the prevention and treatment of hypertension, but its effects on the early metabolic and hemodynamic abnormalities observed in normotensive offspring of hypertensive parents (FH+) have not been studied. We compared high-intensity interval (aerobic interval training, AIT) and moderate-intensity continuous exercise training (CMT) with regard to hemodynamic, metabolic and hormonal variables in FH+ subjects. Forty-four healthy FH+ women (25.0+/-4.4 years) randomized to control (ConFH+) or to a three times per week equal-volume AIT (80-90% of VO(2MAX)) or CMT (50-60% of VO(2MAX)) regimen, and 15 healthy women with normotensive parents (ConFH-; 25.3+/-3.1 years) had their hemodynamic, metabolic and hormonal variables analyzed at baseline and after 16 weeks of follow-up. Ambulatorial blood pressure (ABP), glucose and cholesterol levels were similar among all groups, but the FH+ groups showed higher insulin, insulin sensitivity, carotid-femoral pulse wave velocity (PWV), norepinephrine and endothelin-1 (ET-1) levels and lower nitrite/ nitrate (NOx) levels than ConFH- subjects. AIT and CMT were equally effective in improving ABP (P<0.05), insulin and insulin sensitivity (P<0.001); however, AIT was superior in improving cardiorespiratory fitness (15 vs. 8%; P<0.05), PWV (P<0.01), and BP, norepinephrine, ET-1 and NOx response to exercise (P<0.05). Exercise intensity was an important factor in improving cardiorespiratory fitness and reversing hemodynamic, metabolic and hormonal alterations involved in the pathophysiology of hypertension. These findings may have important implications for the exercise training programs used for the prevention of inherited hypertensive disorder. Hypertension Research (2010) 33, 836-843; doi:10.1038/hr.2010.72; published online 7 May 2010

OXIDATIVE STRESS BIOMARKER RESPONSES TO AN ACUTE SESSION OF HYPERTROPHY-RESISTANCE TRADITIONAL INTERVAL TRAINING AND CIRCUIT TRAINING

Deminice, R, Sicchieri, T, Mialich, MS, Milani, F, Ovidio, PP, and Jordao, AA. Oxidative stress biomarker responses to an acute session of hypertrophy-resistance traditional interval training and circuit training. J Strength Cond Res 25(3): 798-804, 2011-We have studied circuit resistance schemes with high loads as a time-effective alternative to hypertrophy-traditional resistance training. However, the oxidative stress biomarker responses to high-load circuit training are unknown. The aim of the present study was to compare oxidative stress biomarker response with an acute session of hypertrophy-resistance circuit training and traditional interval training. A week after the 1 repetition maximum (1RM) test, 11 healthy and well-trained male participants completed hypertrophy-resistance acute sessions of traditional interval training (3 x 10 repetitions at 75% of the 1RM, with 90-second passive rest) and circuit training (3 x 10 repetitions at 75% of the 1RM, in alternating performance of 2 exercises with different muscle groups) in a randomized and cross-over design. Venous blood samples were collected before (pre) and 10 minutes after (post) the resistance training sessions for oxidative stress biomarker assays. As expected, the time used to complete the circuit training (20.2 +/- 1.6) was half of that needed to complete the traditional interval training (40.3 +/- 1.8). Significant increases (p < 0.05) in thiobarbituric acid reactive substances (40%), creatine kinase (CK) (67%), glutathione (14%), and uric acid (25%) were detected posttraditional interval training session in relation to pre. In relation to circuit training, a significant increase in CK (33%) activity postsession in relation to pre was observed. Statistical analysis did not reveal any other change in the oxidative stress biomarker after circuit training. In conclusion, circuit resistance-hypertrophy training scheme proposed in the current study promoted lower oxidative stress biomarkers and antioxidant modulations compared with resistance traditional interval training.

Interval training program optimization in highly trained endurance cyclists

Purpose: The purpose of this study was to examine the influence of three different high-intensity interval training (HIT) regimens on endurance performance in highly trained endurance athletes. Methods: Before, and after 2 and 4 wk of training, 38 cyclists and triathletes (mean +/- SD; age = 25 +/- 6 yr; mass = 75 +/- 7 kg; (V)over dot O-2peak = 64.5 +/- 5.2 mL.kg(-1).min(-1)) performed: 1) a progressive cycle test to measure peak oxygen consumption ((V)over dotO(2peak)) and peak aerobic power output (PPO), 2) a time to exhaustion test (T-max) at their (V)over dotO(2peak) power output (P-max), as well as 3) a 40-kin time-trial (TT40). Subjects were matched and assigned to one of four training groups (G(1), N = 8, 8 X 60% T-max P-max, 1:2 work:recovery ratio; G(2), N = 9, 8 X 60% T-max at P-max, recovery at 65% HRmax; G(3), N = 10, 12 X 30 s at 175% PPO, 4.5-min recovery; G(CON), N = 11). In addition to G(1) G(2), and G(3) performing HIT twice per week, all athletes maintained their regular low-intensity training throughout the experimental period. Results: All HIT groups improved TT40 performance (+4.4 to +5.8%) and PPO (+3.0 to +6.2%) significantly more than G(CON) (-0.9 to + 1.1 %; P < 0.05). Furthermore, G(1) (+5.4%) and G(2) (+8.1%) improved their (V)over dot O-2peak significantly more than G(CON) (+ 1.0%; P < 0.05). Conclusion: The present study has shown that when HIT incorporates P-max as the interval intensity and 60% of T-max as the interval duration, already highly trained cyclists can significantly improve their 40-km time trial performance. Moreover, the present data confirm prior research, in that repeated supramaximal HIT can significantly improve 40-km time trial performance.

Interval training at 95% and 100% of the velocity at VO2 max: effects on aerobic physiological indexes and running performance

The objective of this study was to analyze the effect of two different high-intensity interval training (HIT) programs on selected aerobic physiological indices and 1500 and 5000 m running performance in well-trained runners. The following tests were completed (n = 17): (i) incremental treadmill test to determine maximal oxygen uptake (VO2max), running velocity associated with VO2 max (VVO2max), and the velocity corresponding to 3.5 mmol/L of blood lactate concentration (vOBLA); (ii) submaximal constant-intensity test to determine running economy (RE); and (iii) 1500 and 5000 m time trials on a 400 m track. Runners were then randomized into 95% vVO(2max) or 100% vVO(2max) groups, and undertook a 4 week training program consisting of 2 HIT sessions (performed at 95% or 100% vVO(2max), respectively) and 4 submaximal run sessions per week. Runners were retested on all parameters at the completion of the training program. The VO2 max values were not different after training for both groups. There was a significant increase in post-training vVO(2 max), RE, and 1500 in running performance in the 100% vVO(2 max) group. The vOBLA and 5000 m running performance were significantly higher after the training period for both groups. We conclude that vOBLA and 5000 m running performance can be significantly improved in well-trained runners using a 4 week training program consisting of 2 HIT sessions (performed at 95% or 100% vVO(2max)) and 4 submaximal run sessions per week. However, the improvement in vVO(2 max), RE, and 1500 in running performance seems to be dependent on the HIT program at 100% vVO(2 max).

Rating of perceived exertion as a tool for prescribing and self regulating interval training: a pilot study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)