Physiological and performance responses of sprint interval training and endurance training in Gaelic football players.

PURPOSE: While ideal for developing aerobic capacity, traditional endurance training (ET) is extremely time-consuming and may lack the specificity to maintain indices of speed and power in team sport athletes. In contrast, low-volume short-duration sprint interval training (SIT) has been shown to improve [Formula: see text]O2max to a similar extent as ET. However, to date, few studies have compared the effects of running-based SIT and ET, on aerobic capacity and indices of speed and power of trained team sport athletes. METHODS: Club level male Gaelic football players were randomly assigned to SIT (n = 13; 26.5 ± 4.87 years) or ET (n = 12; 25.4 ± 2.58 years) groups. Participants trained 3 days week-1 for 6 weeks. [Formula: see text]O2max, RE, v[Formula: see text]O2max, blood lactate concentrations, Wingate test performance, running speed, jump performance and intermittent endurance performance (IEP) were measured at baseline and after 6 weeks. RESULTS: An increase in [Formula: see text]O2max (p < 0.05), v[Formula: see text]O2max (p < 0.001) and IEP (p < 0.001) following 6 weeks of both SIT and ET was observed. Wingate mean power (p < 0.001), peak power (p < 0.001) and fatigue index (p < 0.005) were all significantly improved following training in both groups. Velocity at LT was significantly higher and performance in the 20-m running speed and VJ tests were significantly reduced post training in the ET group (all p < 0.005). CONCLUSION: Despite the large difference in total training time, a running-based protocol of SIT is a time efficient training method for improving aerobic capacity and IEP while maintaining indices of lower body power and running speed in team-sport players.

A Single Bout of Foam Rolling Increases Flexibility of the Hip Adductor Muscles without Compromising Strength.

Foam rolling (FR) is a method of self-myofascial release (SMR) implemented to reduce tension in underlying soft tissue, leading to increased range of motion (ROM). The hip adductor muscles of the groin are commonly less flexible and often a site for soft tissue injuries. Limited research has been done to determine the most effective flexibility exercises to increase ROM in the groin muscles prior to exercise without comprising strength. The purpose was to determine the effect of an acute bout of FR on passive groin flexibility and strength. Randomized crossover study with 3 × 2 (Condition × Time) repeated measures ANOVA statistical design. 40 volunteers (n = 20 males; n = 20 females) with limited flexibility in groin ROM participated. Following warm-up, maximal voluntary isometric contraction (MVC) and static ROM were measured pre and postintervention. Conditions included 60 seconds of FR, SS, and CON. The Condition × Time interaction was not significant for MVC or ROM. A main effect of time showed a significant increase in ROM from pre to post for FR (1.2°, p < 0.001), SS (1.0°, p < 0.001), and CON (0.5°, p = 0.039). No significant changes in MVC were observed for FR from pre to post (p > 0.05), whereas SS and CON both increased (p < 0.05). An increase in passive groin ROM after acute bouts of SMR or SS without compromising MVC was observed. This suggests that 60 seconds of FR may be employed before exercise to improve flexibility without strength decrement.

Time course analysis reveals gene-specific transcript and protein kinetics of adaptation to short-term aerobic exercise training in human skeletal muscle.

Repeated bouts of episodic myofibrillar contraction associated with exercise training are potent stimuli for physiological adaptation. However, the time course of adaptation and the continuity between alterations in mRNA expression and protein content are not well described in human skeletal muscle. Eight healthy, sedentary males cycled for 60 min at 80% of peak oxygen consumption (VO2peak) each day for fourteen consecutive days, resulting in an increase in VO2peak of 17.5±3.8%. Skeletal muscle biopsies were taken at baseline, and on the morning following (+16 h after exercise) the first, third, seventh, tenth and fourteenth training sessions. Markers of mitochondrial adaptation (Cyt c and COXIV expression, and citrate synthase activity) were increased within the first week of training, but the mtDNA/nDNA ratio was unchanged by two weeks of training. Accumulation of PGC-1α and ERRα protein during training suggests a regulatory role for these factors in adaptations of mitochondrial and metabolic gene expression. A subset of genes were transiently increased after one training session, but returned to baseline levels thereafter, which is supportive of the concept of transcriptional capacity being particularly sensitive to the onset of a new level of contractile activity. Thus, gene-specific temporal patterns of induction of mRNA expression and protein content are described. Our results illustrate the phenomenology of skeletal muscle plasticity and support the notion that transcript level adjustments, coupled to accumulation of encoded protein, underlie the modulation of skeletal muscle metabolism and phenotype by regular exercise.

2-D DIGE analysis of the mitochondrial proteome from human skeletal muscle reveals time course-dependent remodelling in response to 14 consecutive days of endurance exercise training.

Adaptation of skeletal muscle to repeated bouts of endurance exercise increases aerobic capacity and improves mitochondrial function. However, the adaptation of human skeletal muscle mitochondrial proteome to short-term endurance exercise training has not been investigated. Eight sedentary males cycled for 60 min at 80% of peak oxygen consumption (VO(2peak) ) each day for 14 consecutive days, resulting in an increase in VO(2peak) of 17.5±3.8% (p<0.01). Mitochondria-enriched protein fractions from skeletal muscle biopsies taken from m. vastus lateralis at baseline, and on the morning following the 7th and 14th training sessions were subjected to 2-D DIGE analysis with subsequent MS followed by database interrogation to identify the proteins of interest. Thirty-one protein spots were differentially expressed after either 7 or 14 days of training (ANOVA, p<0.05). These proteins included subunits of the electron transport chain, enzymes of the tricarboxylic acid cycle, phosphotransfer enzymes, and regulatory factors in mitochondrial protein synthesis, oxygen transport, and antioxidant capacity. Several proteins demonstrated a time course-dependent induction during training. Our results illustrate the phenomenon of skeletal muscle plasticity with the extensive remodelling of the mitochondrial proteome occurring after just 7 days of exercise training suggestive of enhanced capacity for adenosine triphosphate generation at a cellular level.

Effect of prior exercise on postprandial lipemia and markers of inflammation and endothelial activation in normal weight and overweight adolescent boys.

Postprandial lipemia (PPL) is associated with impaired endothelial function and inflammation. Acute exercise reduces PPL in adults. This investigation examined the effect of an acute bout of exercise on postprandial changes in triglycerides (TG), glucose, insulin, inflammation [white blood cell count (WBC), interleukin-6 (IL-6) tumor necrosis factor-alpha, C-reactive protein (CRP)] and endothelial activation [soluble intercellular adhesion molecule-1 (sICAM-1), vascular adhesion molecule-1 (sVCAM-1)] following a high-fat meal in adolescents. Ten normal weight (NW) (BMI, 20.9 +/- 1.7 kg m(-2); 15.6 +/- 0.7 years) and eight overweight (OW) (BMI, 28.3 +/- 3.6 kg m(-2); 15.9 +/- 0.4 years) adolescent boys underwent two 6-h oral fat tolerance tests (OFTT) separated by 7-10 days. On the evening prior to each OFTT, subjects either rested or completed a treadmill exercise bout (65% V(O)(2max); 600 kcal expended). Exercise reduced (P < 0.01) the postprandial TG area under the curve by approximately 20% in the NW and OW groups. The postprandial glucose and insulin response did not differ between the control and exercise trials or between the NW and OW groups. Circulating leukocytes and plasma IL-6 levels increased (P < 0.01) in the NW and OW groups 6 h following the OFTT in both experimental conditions. There were no changes in CRP, sVCAM-1 or sICAM-1 following the OFTT and there were no differences between experimental condition or NW and OW groups. In conclusion, a moderate exercise bout prior to a high-fat meal effectively reduces postprandial TG concentrations to a similar degree in both NW and OW adolescents, but does not reduce the concomitant postprandial increase in WBC or IL-6.

The endothelial microparticle response to a high fat meal is not attenuated by prior exercise.

Triglyceride-rich postprandial lipoproteins are known to activate endothelial cells in vitro, contributing to atherosclerosis. Endothelial microparticles (EMP) are membranous vesicles released into the circulation from vascular endothelial cells that permit cell activation to be monitored in vivo. The objective of the study was to examine changes in EMP following a high fat meal, consumed with and without prior exercise. Eight recreationally active young men underwent two oral fat tolerance tests following either 100 min exercise at 70% VO(2)peak (EX trial) or no exercise (CON trial) on the previous evening. Postprandial triglycerides were reduced (1.97 +/- 0.31 vs. 1.17 +/- 0.13 mmol L(-1), p < 0.05) and HDL-cholesterol (HDL-C) increased (1.20 +/- 0.07 vs. 1.30 +/- 0.08 mmol L(-1), p < 0.05) in the EX compared to CON trial. EMP (CD31+/42b-) increased postprandially (p < 0.05). However, counts were not different between trials (postprandial CON and EX trial counts x 10(3 )microL(-1), 3.10 +/- 0.14 vs. 3.26 +/- 0.37). There were no changes in sICAM-1 or sVCAM-1 postprandially and no differences between trials. Interleukin-6 (IL-6) and leukocytes increased postprandially (p < 0.05). IL-6 values were not different between trials. Leukocytes were higher at 0 h in the EX trial with CON and EX trial values similar at 6 h. EMP, but not sICAM-1 or sVCAM-1, increase in response to a high fat meal. However, EMP are not attenuated by acute exercise, despite a considerable reduction in postprandial lipemia and an increase in HDL-C.