Use of NIRS to explore skeletal muscle oxygenation during different training sessions in professional boxing.

PURPOSE: The physiological examination of boxing has been limited to systemic response in amateur athletes. The demands of professional boxing have been overlooked, despite the different competition format. We sought to determine the physiological demands placed on skeletal muscle in professional boxing. METHODS: Ten male professional boxers (age 26 ± 5 years, height 177 ± 4 cm, weight 71 ± 6 kg) were recruited for this observational study. On different days, the athletes completed 6 × 3 min rounds of pad, bag or spar-based training with 1 min recovery between each round. Prior to each session, participants put on a heart rate monitor and near-infrared spectroscopy attached to the belly of the rectus femoris muscle to record heart rate and muscle oxygenation. RESULTS: There were significantly less punches thrown in sparring compared to other training modalities (p < 0.001). Skeletal muscle oxygenation across training modalities consisted of a delay, fast desaturation and steady state. Across rounds there was a significant increase in time delay for desaturation (p = 0.016), rate of fast desaturation (p < 0.001) and duration of fast desaturation (p = 0.019). There was a significant difference in sparring for the heart rate where skeletal muscle oxygenation changes occurred compared to pads or bag sessions (p < 0.001). CONCLUSION: The findings highlight differences in the skeletal muscle response to the different training modalities. Practitioners need to be aware of the muscular demands of each session to allow optimal adaptation across a training camp. Training needs to allow the skeletal muscle to achieve a new oxygenation steady state rapidly to promote efficient performance across rounds.

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 Physical Demands of Match-Play in Academy and Senior Soccer Players from the Scottish Premiership.

The present study aimed to assess the physical match performance among senior and youth soccer players from an elite Scottish Premiership club during the 2021/2022 season. Twenty-two first team (25.9 ± 4.5 years, 78.3 ± 8.2 kg, 1.82 ± 0.07 cm) and 16 youth players (16.8 ± 0.9 years, 70.1 ± 6.8 kg, 177 ± 5.8 cm) were examined. A selection of physical match performance variables were measured using a global positioning system. Linear mixed-effect regressions revealed for all examined variables no significant differences between first team and U-18 players and no significant differences between playing level by position interaction. Across both teams, Centre Backs compared to Wing Backs, showed a 295 m (p < 0.01) lower high-intensity distance, and performed on average 36 fewer very-high intensity decelerations (p = 0.03). Comparing to Wide Midfielders, Centre Backs showed lower total (1297 m, p = 0.01), high-intensity (350 m, p = 0.01), and sprint (167 m, p < 0.01) distances. Sprint distance was also lower in Centre Backs vs. Strikers (118 m, p = 0.03), and in Central Midfielders vs. both Strikers (104 m, p = 0.03) and Wide Midfielders (154 m, p = 0.01). The present findings highlight the physical match performance of elite Scottish players and provide useful information within the context of understanding how methods of physical development of youth soccer are implemented in different countries.

Weekly Vitamin D3 supplementation improves aerobic performance in combat sport athletes.

AbstractVitamin D3 supplementation can affect the strength and power of an athlete, however the effect on endurance performance remains unclear. Twenty-seven recreational male combat athletes with at least 12 months experience within combat sports were recruited (age: 24 ± 4 years, stature: 176 ± 6 cm, weight: 77 ± 14 kg). Participants completed baseline testing for blood haemoglobin and haematocrit, upper and lower body VO2peak and upper and lower body Wingate. Following testing participants were stratified to 50,000IU (D1), 80,000IU (D2) or 110,000IU (D3) of vitamin D3 per week. They then completed a 6-week placebo period followed by a 6-week supplementation period. Retesting was carried out after the placebo and supplementation period. There was a significant effect for time for haemoglobin and haematocrit, upper and lower body VO2peak and upper body Wingate power (P < 0.01) but no effect for dose of vitamin D given. Performance data were normalised to vitamin D intake and there was a moderate effect size between D1 and D2 for lower body VO2peak (d = 0.6), upper body VO2peak (d = 0.13) and upper body average power (d = 0.75), with a large effect size between D1 and D2 for haemoglobin (d = 1.19), haematocrit (d = 0.93) and upper body peak power (d = 0.95). There was a large effect size for D1 compared to D3 for all variables (d > 0.8). Therefore, there is no additional benefit to increasing dose above 50,000IU vitamin D per week. Given the endurance adaptations from vitamin D supplementation and the importance of endurance for combat performance, recreational combat athletes should supplement at 50,000IU per week for six weeks.

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.

Active Recovery Induces Greater Endurance Adaptations When Performing Sprint Interval Training.

Yamagishi, T and Babraj, J. Active recovery induces greater endurance adaptations when performing sprint interval training. J Strength Cond Res 33(4): 922-930, 2019-This study sought to determine effects of recovery intensity on endurance adaptations during sprint interval training (SIT). Fourteen healthy young adults (male: 9 and female: 5) were allocated to 1 of 2 training groups: active recovery group (ARG, male: 4 and female: 3) or passive recovery group (PRG, male: 5 and female: 2). After having completed a 2-week control period, both groups performed 6 sessions of 4- to 6 30-second sprints interspersed with 4-minute recovery over 2 weeks. However, only ARG cycled at 40% V[Combining Dot Above]O2peak during the 4-minute recovery periods, while PRG rested on the bike or cycled unloaded. After the 2-week training intervention, both groups improved 10-km time-trial performance to a similar extent (ARG: 8.6%, d = 1.60, p = 0.006; PRG: 6.7%, d = 0.96, p = 0.048) without gains in V[Combining Dot Above]O2peak. However, critical power was increased by ARG only (7.9%, d = 1.75, p = 0.015) with a tendency of increased maximal incremental power output (5.3%, d = 0.88, p = 0.063). During the training, active recovery maintained V[Combining Dot Above]O2 and heart rate at a higher level compared with passive recovery (V[Combining Dot Above]O2: p = 0.005, HR: p = 0.018), suggesting greater cardiorespiratory demands with the active recovery. This study demonstrated that greater endurance performance adaptations are induced with active recovery when performing SIT over a short time frame. The findings of the current study indicate that, with active recovery, individuals can gain greater training benefits without increasing total training commitment time. Further studies are required to determine whether differences are seen with recovery intensity over a longer period.

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.

The effect of low volume sprint interval training in patients with non-alcoholic fatty liver disease.

OBJECTIVES: Exercise is an important part of disease management in patients with non-alcoholic fatty liver disease (NAFLD), but adherence to current exercise recommendations is poor. Novel low-volume sprint interval training (SIT) protocols with total training time commitments of ≤30 min per week have been shown to improve cardiometabolic risk and functional capacity in healthy sedentary participants, but the efficacy of such protocols in the management of NAFLD remains unknown. The aim of the present study was to examine whether a low-volume SIT protocol can be used to improve liver function, insulin resistance, body composition, physical fitness, cognitive function and general well-being in patients with NAFLD. METHODS: In the present study, 7 men and 2 women with NAFLD (age: 45 ± 8 y, BMI: 28.7 ± 4.1 kg·m-2) completed a 6-week control period followed by 6 weeks of twice-weekly SIT sessions (5-10 × 6-s 'all-out' cycle sprints). Body composition, blood pressure, liver function, metabolic function, functional capacity, cognitive function and quality of life were assessed at baseline, following the control period, and following the SIT intervention. RESULTS: Walking speed during the walk test (+12%), estimated V̇O2max (+8%), verbal fluency (+44%), and blood platelet count (+12%; all p < 0.05) significantly increased during the control period. These measures remained significantly raised compared to baseline following the SIT intervention, but did not significantly change any further compared to the post-control time-point. Diastolic blood pressure decreased from 87 ± 10 to 77 ± 8 mm Hg from the end of the control period to the end of the SIT intervention (p < 0.05). CONCLUSION: This study does not support the use of 6 weeks of a low volume SIT protocol involving twice-weekly sessions with 5-10 × 6-s 'all-out' cycle sprints as an intervention for NAFLD disease management.

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.

Anabolic resistance does not explain sarcopenia in patients with type 2 diabetes mellitus, compared with healthy controls, despite reduced mTOR pathway activity.

BACKGROUND: Ageing and type 2 diabetes mellitus (T2DM) are risk factors for skeletal muscle loss. We investigated whether anabolic resistance to feeding might underlie accelerated muscle loss in older people with T2DM and whether dysregulated mTOR signalling was implicated. SUBJECTS: 8 obese men with T2DM, and 12 age-matched controls were studied (age 68 ± 3 vs. 68±6 y; BMI: 30 ± 2 vs. 27 ± 5 kg m-2). METHODS: Body composition was measured by dual-X-ray absorptiometry. Insulin and glucose were clamped at post-absorptive concentrations (13 ± 2 vs. 9 ± 3 mU l-1; 7.4 ± 1.9 vs. 4.6 ± 0.4 mmol l-1; T2DM vs. controls). Fractional synthetic rates (FSR) of myofibrillar and sarcoplasmic proteins were measured as the rate of incorporation of [13C] leucine during a primed, constant infusion of [1-13C] α-ketoisocaproic acid, 3 h after 10 or 20 g of essential amino acids (EAA) were orally administered. Protein expression of total and phosphorylated mTOR signalling proteins was determined by Western blot analysis. RESULTS: Despite a significantly lower appendicular lean mass index and a greater fat mass index in T2DM vs. controls, basal myofibrillar and sarcoplasmic and post-prandial myofibrillar FSR were similar. After 20 g EAA, stimulation of sarcoplasmic FSR was slightly blunted in T2DM patients. Furthermore, feeding 20 g EAA increased phosphorylation of mTOR, p70S6k and 4E-BP1 by 60-100% in controls with no response observed in T2DM. CONCLUSIONS: There was clear dissociation between changes in mTOR signalling versus changes in protein synthesis rates. However, the intact anabolic response of myofibrillar FSR to feeding in both groups suggests anabolic resistance may not explain accelerated muscle loss in T2DM.

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.

Efficacy of a Four-Week Uphill Sprint Training Intervention in Field Hockey Players.

Jakeman, JR, McMullan, J, and Babraj, JA. Efficacy of a four-week uphill sprint training intervention in field hockey players. J Strength Cond Res 30(10): 2761-2766, 2016-Current evidence increasingly suggests that very short, supramaximal bouts of exercise can have significant health and performance benefits. Most research conducted in the area, however, uses laboratory-based protocols, which can lack ecological validity. The purpose of this study was to examine the effects of a high-intensity sprint training program on hockey-related performance measures. Fourteen semiprofessional hockey players either completed a 4-week high-intensity training (HIT) intervention, consisting of a total of 6 sessions of HIT, which progressively increased in volume (n = 7), or followed their normal training program (Con; n = 7). Straight-line sprint speed, with and without a hockey stick and ball, and slalom sprint speed, with and without a hockey stick and ball, were used as performance indicators. Maximal sprint speed over 22.9 m was also assessed. On completion of the 4-week intervention, straight-line sprint speed improved significantly in the HIT group (∼3%), with no changes in performance for the Con group. Slalom sprint speed, both with and without a hockey ball, was not significantly different after the training program in either group. Maximal sprint speed improved significantly (12.1%) in the HIT group, but there was no significant performance change in the Con group. The findings of this study indicate that a short period of HIT can significantly improve hockey-related performance measures and could be beneficial to athletes and coaches in field settings.

Whole-Body Vibration Training and Its Application to Age-Related Performance Decrements: An Exploratory Analysis.

Middle age is associated with a pronounced decline in power and flexibility. Whilst whole-body vibration training (WBVT) improves performance in a range of populations, whether WBVT can improve muscle power and flexibility in a middle-aged population is not known. The present study aimed to determine the influence of 5 weeks progressive WBVT in middle-aged (45-55 years) and younger (20-30 years) recreationally active females. Participants in each age group were randomly allocated to an intervention (WBVT) or control group. The WBVT groups trained for 5 weeks on a vibration platform, while the control groups performed identical exercises, with no vibration. Prior to, and after, the 5-week study vertical countermovement jump (VCMJ) and range of motion (ROM) performance were measured. WBVT significantly (p = 0.001) improved VCMJ performance when compared to the control groups. This improvement was significantly (p = 0.001) greater in the middle-aged compared with the younger WBVT group. WBVT significantly (p = 0.001) improved ROM irrespective of age. Taken together, these results suggest that WBVT can off-set age related performance decrements, which has therapeutic implications for musculoskeletal aging. Therefore, WBVT could be undertaken to minimise age-related performance deterioration in middle-aged female populations.

Influence of recovery intensity on oxygen demand and repeated sprint performance.

BACKGROUND: This study aimed to determine effects of recovery intensity (passive, 20%, 30% and 40% V̇O2peak) on oxygen uptake kinetics, performance and blood lactate accumulation during repeated sprints. METHODS: Seven moderately-trained male participants (V̇O2peak: 48.1±5.1 mL/kg/min) performed four 30-second repeated Wingate tests on four separate occasions. RESULTS: Recovery of V̇O2 between sprints was prolonged with recovery intensity (time required to reach 50% V̇O2peak: passive: 50±9 s; 20%: 81±17 s; 30%: 130±43 s; 40%: 188±62 s, P<0.001), while V̇O2-to-sprint work ratio was mainly increased by the higher intensities (passive: 138±17 mL/min/kJ; 20%: 149±14 mL/min/kJ; 30%: 159±15 mL/min/kJ; 40%: 158±17 mL/min/kJ, P=0.001). The decline in peak power tended to be greater in the higher intensity conditions during sprint 2 (passive: 7.4±5.4%; 20%: 5.8±7.9%; 30%: 12.7±7.4%; 40%: 12.7±5.5%, P=0.052), whereas average power was less decreased with recovery intensity during sprint 4 (passive: 22.4±8.9%; 20%: 19.9±6.1%; 30%: 18.4±7.3%; 40%: 16.6±6.2%, P=0.036). Blood lactate was not different with recovery intensity (P=0.251). CONCLUSIONS: The present study demonstrated that while the higher recovery intensities induce prolonged oxygen recovery and impaired peak power restoration during the initial sprints, those intensities provide a greater aerobic contribution to sprint performance, resulting in better power maintenance during the latter sprints.

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.

High intensity training improves health and physical function in middle aged adults.

High intensity training (HIT) is effective at improving health; however, it is unknown whether HIT also improves physical function. This study aimed to determine whether HIT improves metabolic health and physical function in untrained middle aged individuals. Fourteen (three male and eleven female) untrained individuals were recruited (control group n = 6: age 42 ± 8 y, weight 64 ± 10 kg, BMI 24 ± 2 kg·m-2 or HIT group n = 8: age 43 ± 8 y, weight 80 ± 8 kg, BMI 29 ± 5 kg·m-2). Training was performed twice weekly, consisting of 10 × 6-second sprints with a one minute recovery between each sprint. Metabolic health (oral glucose tolerance test), aerobic capacity (incremental time to exhaustion on a cycle ergometer) and physical function (get up and go test, sit to stand test and loaded 50 m walk) were determined before and after training. Following eight weeks of HIT there was a significant improvement in aerobic capacity (8% increase in VO2 peak; p < 0.001), physical function (11%-27% respectively; p < 0.05) and a reduction in blood glucose area under the curve (6% reduction; p < 0.05). This study demonstrates for the first time the potential of HIT as a training intervention to improve skeletal muscle function and glucose clearance as we age.

The potential influence of perception of achievement on performance in volitional time-to-exhaustion cycle ergometer trials.

The purpose of this short communication was to report the findings of an investigation of the potential influence of spontaneous goal setting on subjects undertaking maximal fitness testing. Subjects were asked to complete a single incremental volitional time-to-exhaustion cycle ergometer trial. The final minute of the trial, after the last increase in increment in resistance, was broken down into six 10-second intervals and a frequency count made of how many subjects stopped within each interval. A chi-square test was used to determine that there was a significant difference between the expected and the observed frequencies (p < 0.05), with 45% of subjects stopping in the first interval (0-10 seconds) and 0% within the last interval (51-60 seconds). Reflections of the subjects revealed that those who were close to exhaustion but near to reaching the next increment of resistance were more likely to "push on." However, despite having been told to keep going as long as they could, subjects upon reaching that increment stopped almost immediately as they believed they could not manage to reach the next increment. This suggests a potential psychological element related to goal achievement that influences performance in incremental volitional time-to-exhaustion cycle ergometer trials. Practically, this means that the information participants have available on which to base goals (level of increment, time, etc.) needs to be minimized to prevent spontaneous goal setting.

Extremely short duration high-intensity training substantially improves endurance performance in triathletes.

High-intensity training (HIT) involving 30-s sprints is an effective training regimen to improve aerobic performance. We tested whether 6-s HITs can improve aerobic performance in triathletes. Six subelite triathletes (age, 40 ± 9 years; weight, 86 ± 11 kg; body mass index, 26 ± 3 kg·m⁻²) took part in cycle HIT and 6 endurance-trained subelite athletes (age, 36 ± 9 years; weight, 82 ± 11 kg; BMI, 26 ± 3 kg·m⁻²) maintained their normal training routine. Before and after 2 weeks of HIT, involving 10 × 6-s sprints or normal activity, participants performed a self-paced 10-km time trial and a time to exhaustion test on a cycle ergometer. Finger prick blood samples were taken throughout the time to exhaustion test to determine blood lactate concentration. Two weeks of HIT resulted in a 10% decrease in self-paced 10-km time trial (p = 0.03) but no significant change in time to exhaustion. The time taken to reach onset of blood lactate accumulation (OBLA, defined as the point where blood lactate reaches 4 mmol·L⁻¹) was significantly increased following 2 weeks of HIT (p = 0.003). The change in time trial performance was correlated to the change in time taken to reach OBLA (R² = 0.63; p = 0.001). We concluded that a very short duration HIT is a very effective training regimen to improve aerobic performance in subelite triathletes and this is associated with a delay in blood lactate build-up.