Physiol Behav. 2011 Sep 10. [Epub ahead of print]
Attenuated RPE and leg pain in response to short-term high-intensity interval training.
Astorino TA, Allen RP, Roberson DW, Jurancich M, Lewis R, McCarthy K.
This study examined the effect of 6days of high intensity interval training (HIT) on rating of perceived exertion (RPE) and leg pain. Eleven men (age and VO(2)max=25.3±5.5year and 45.6±mL/kg/min) and 9 women (age and VO(2)max=25.2±3.1year and 41.1±6.1mL/kg/min) with similar activity level and VO(2)max underwent HIT consisting of repeated Wingate tests separated by 5min recovery over a 2-3 week period. Five men and four women served as controls and did not perform HIT. Four minutes after each bout across all days of training, RPE and leg pain were recorded using categorical scales. Repeated measure ANOVA was used to assess differences in RPE and leg pain in response to acute bouts and days of HIT. Data revealed that RPE and pain increased (p<0.05) after bout 1 to after bout 4. Compared to day 1 (6.3±1.9), RPE after bout 4 (5.0±1.4) decreased (p=0.001) in response to 6d of HIT. Training significantly reduced (p<0.05) leg pain, as pain declined from day 1 (6.20±2.29) of HIT versus day 6 (5.20±2.04). Data show that RPE and leg pain are significantly attenuated by 6d of HIT, which is likely due to the physiological adaptations accrued in response to this modality of training.
J Appl Physiol. 2001 Jun;90(6):2019-24.
Effects of high-intensity swimming training on GLUT-4 and glucose transport activity in rat skeletal muscle.
Terada S, Yokozeki T, Kawanaka K, Ogawa K, Higuchi M, Ezaki O, Tabata I.
This study was performed to assess the effects of short-term, extremely high-intensity intermittent exercise training on the GLUT-4 content of rat skeletal muscle. Three- to four-week-old male Sprague-Dawley rats with an initial body weight ranging from 45 to 55 g were used for this study. These rats were randomly assigned to an 8-day period of high-intensity intermittent exercise training (HIT), relatively high-intensity intermittent prolonged exercise training (RHT), or low-intensity prolonged exercise training (LIT). Age-matched sedentary rats were used as a control. In the HIT group, the rats repeated fourteen 20-s swimming bouts with a weight equivalent to 14, 15, and 16% of body weight for the first 2, the next 4, and the last 2 days, respectively. Between exercise bouts, a 10-s pause was allowed. RHT consisted of five 17-min swimming bouts with a 3-min rest between bouts. During the first bout, the rat swam without weight, whereas during the following four bouts, the rat was attached to a weight equivalent to 4 and 5% of its body weight for the first 5 days and the following 3 days, respectively. Rats in the LIT group swam 6 h/day for 8 days in two 3-h bouts separated by 45 min of rest. In the first experiment, the HIT, LIT, and control rats were compared. GLUT-4 content in the epitrochlearis muscle in the HIT and LIT groups after training was significantly higher than that in the control rats by 83 and 91%, respectively. Furthermore, glucose transport activity, stimulated maximally by both insulin (2 mU/ml) (HIT: 48%, LIT: 75%) and contractions (25 10-s tetani) (HIT: 55%, LIT: 69%), was higher in the training groups than in the control rats. However, no significant differences in GLUT-4 content or in maximal glucose transport activity in response to both insulin and contractions were observed between the two training groups. The second experiment demonstrated that GLUT-4 content after HIT did not differ from that after RHT (66% higher in trained rats than in control). In conclusion, the present investigation demonstrated that 8 days of HIT lasting only 280 s elevated both GLUT-4 content and maximal glucose transport activity in rat skeletal muscle to a level similar to that attained after LIT, which has been considered a tool to increase GLUT-4 content maximally.
Eur J Appl Physiol. 2011 Jul;111(7):1279-86. Epub 2010 Dec 4.
Adaptations to high-intensity training are independent of gender.
Astorino TA, Allen RP, Roberson DW, Jurancich M, Lewis R, McCarthy K, Trost E.
The purpose of this study was to identify potential gender discrepancies in adaptation to low-volume high-intensity interval training (HIT). Active, young men (n = 11, age = 25.3 ± 5.5 years) and women (n = 9, age = 25.2 ± 3.1 years) matched for age, physical activity, and VO(2max) completed six sessions of HIT separated by 48 h over a 2-3 week period. Subjects completed four Wingate tests on days 1 and 2, five on days 3 and 4, and six on days 5 and 6. A control group of five men and four women (age = 22.8 ± 2.8 years) completed all testing, but did not perform HIT. Changes in VO(2max), oxygen (O(2)) pulse, peak/mean power output, fatiguability, substrate oxidation, and voluntary force production of the knee flexors and extensors were examined pre- and post-training with repeated measures ANOVA, with gender and group as between-subjects variables. Results showed significant (p < 0.05) improvements in VCO(2max) and peak/mean power output in response to HIT, as well as reduced respiratory exchange ratio and heart rate during submaximal exercise. The magnitude of change in VO(2max) (5.9 vs. 6.8%), power output (10.4-14.9% vs. 9.1-10.9%), and substrate oxidation was similar (p > 0.05) between men and women. Data show that adaptations to 6 days of low-volume HIT are similar in men and women matched for VO(2max) and physical activity.
Int J Sport Nutr Exerc Metab. 2011 Feb;21(1):27-32.
Effect of caffeine intake on pain perception during high-intensity exercise.
Astorino TA, Terzi MN, Roberson DW, Burnett TR.
Caffeine has been shown to reduce leg-muscle pain during submaximal cycle ergometry, as well as in response to eccentric exercise. However, less is known about its analgesic properties during non-steady-state, high-intensity exercise. The primary aim of this study was to examine the effect of 2 doses of caffeine on leg pain and rating of perceived exertion (RPE) during repeated bouts of high-intensity exercise. Fifteen active men (age 26.4 ± 3.9 yr) completed 2 bouts of 40 repetitions of “all-out” knee extension and flexion of the dominant leg at a contraction velocity equal to 180°/s. Before each trial, subjects abstained from caffeine intake and intense exercise for 48 hr. Over 3 days separated by 48 hr, subjects ingested 1 of 3 treatments (5 mg/kg or 2 mg/kg of anhydrous caffeine or placebo) in a randomized, single-blind, counterbalanced, crossover design. Leg-muscle pain and RPE were assessed during and after exercise using established categorical scales. Across all treatments, pain perception was significantly increased (p < .05) during exercise, as well as from Bout 1 to 2, yet there was no effect (p > .05) of caffeine on pain perception or RPE. Various measures of muscle function were improved (p < .05) with a 5-mg/kg caffeine dose vs. the other treatments. In the 5-mg/kg trial, it is plausible that subjects were able to perform better with similar levels of pain perception and exertion.