The Additional Effect of Training Above the Maximal Metabolic Steady State on VO2peak, Wpeak and Time-Trial Performance in Endurance-Trained Athletes: A Systematic Review, Meta-analysis, and Reality Check.

BACKGROUND: To improve sport performance, athletes use training regimens that include exercise below and above the maximal metabolic steady state (MMSS). OBJECTIVE: The objective of this review was to determine the additional effect of training above MMSS on VO2peak, Wpeak and time-trial (TT) performance in endurance-trained athletes. METHODS: Studies were included in the review if they (i) were published in academic journals, (ii) were in English, (iii) were prospective, (iv) included trained participants, (v) had an intervention group that contained training above and below MMSS, (vi) had a comparator group that only performed training below MMSS, and (vii) reported results for VO2peak, Wpeak, or TT performance. Medline and SPORTDiscus were searched from inception until February 23, 2023. RESULTS: Fourteen studies that ranged from 2 to 12 weeks were included in the review. There were 171 recreational and 128 competitive endurance athletes. The mean age and VO2peak of participants ranged from 15 to 43 years and 38 to 68 mL·kg-1·min-1, respectively. The inclusion of training above MMSS led to a 2.5 mL·kg-1·min-1 (95% CI 1.4-3.6; p < 0.01; I2 = 0%) greater improvement in VO2peak. A minimum of 81 participants per group would be required to obtain sufficient power to determine a significant effect (SMD 0.44) for VO2peak. No intensity-specific effect was observed for Wpeak or TT performance, in part due to a smaller sample size. CONCLUSION: A single training meso-cycle that includes training above MMSS can improve VO2peak in endurance-trained athletes more than training only below MMSS. However, we do not have sufficient evidence to conclude that concurrent adaptation occurs for Wpeak or TT performance.

Effect of Interval Training on the Factors Influencing Maximal Oxygen Consumption: A Systematic Review and Meta-Analysis.

BACKGROUND: The maximal rate of oxygen consumption (VO2max) is an important measure in exercise science as it is an indicator of cardiorespiratory fitness. Individual studies have identified central and peripheral adaptions to interval training that may underlie improvements in VO2max, but there is no compilation of results. OBJECTIVE: We aimed to systematically review the adaptive responses to high-intensity interval training (HIIT) and sprint interval training (SIT) on the central and peripheral factors influencing VO2max in healthy individuals. DATA SOURCES: SPORTDiscus and MEDLINE (up to and including 13 June, 2020) were explored to conduct the literature search. STUDY SELECTION: Reviewed studies met the following criteria: (1) were in the English language; (2) prospective in nature; (3) included at least three interval sessions or were at least 1 week in duration; (4) contained HIIT or SIT; (5) involved participants between the ages of 18 and 65 years; and (6) included at least one of the following central (blood volume, plasma volume, hemoglobin mass, left ventricular mass, maximal stroke volume, maximal cardiac output) or peripheral factors (capillary density, maximal citrate synthase activity, mitochondrial respiration associated with VO2max). RESULTS: Thirty-two studies (369 participants, 49 were female) were included in the quantitative analyses, consisting of both HIIT (n = 18) and SIT (n = 17) interventions. There were only statistically significant changes in hematological measures (plasma volume) following HIIT. There was a significant increase in left ventricular mass following HIIT (7.4%, p < 0.001) and SIT (5.3%, p = 0.007) in inactive individuals, though the change following SIT may be misleading. There was only a significant increase in maximal stroke volume (14.1%, p = 0.015) and maximal cardiac output (12.6%, p = 0.002) following HIIT. In addition to central factors, there was a significant increase in capillary density (13.8%, p < 0.001) following SIT in active individuals. With respect to maximal citrate synthase activity, there were improvements following HIIT (20.8%, p < 0.001) and SIT (15.7%, p < 0.001, I2 = 97%) in active individuals. The results for mitochondrial respiration suggested that there was no statistically significant improvement following HIIT (5.0%, p = 0.585). CONCLUSIONS: Improvements in the central and peripheral factors influencing VO2max were dependent on the interval type. Only HIIT led to a statistically significant improvement in cardiac function. Both HIIT and SIT increased maximal citrate synthase activity, while changes in other peripheral measures (capillary density, mitochondrial respiration) only occurred with SIT.

Programming Interval Training to Optimize Time-Trial Performance: A Systematic Review and Meta-Analysis.

BACKGROUND: Interval training has become an essential component of endurance training programs because it can facilitate a substantial improvement in endurance sport performance. Two forms of interval training that are commonly used to improve endurance sport performance are high-intensity interval training (HIIT) and sprint interval training (SIT). Despite extensive research, there is no consensus concerning the optimal method to manipulate the interval training programming variables to maximize endurance performance for differing individuals. OBJECTIVE: The objective of this manuscript was to perform a systematic review and meta-analysis of interval training studies to determine the influence that individual characteristics and training variables have on time-trial (TT) performance. DATA SOURCES: SPORTDiscus and Medline with Full Text were explored to conduct a systematic literature search. STUDY SELECTION: The following criteria were used to select studies appropriate for the review: 1. the studies were prospective in nature; 2. included individuals between the ages of 18 and 65 years; 3. included an interval training (HIIT or SIT) program at least 2 weeks in duration; 4. included a TT test that required participants to complete a set distance; 5. and programmed HIIT by power or velocity. RESULTS: Twenty-nine studies met the inclusion criteria for the quantitative analysis with a total of 67 separate groups. The participants included males (n = 400) and females (n = 91) with a mean group age of 25 (range 19-45) years and mean [Formula: see text] of 52 (range 32-70) mL·kg-1·min-1. The training status of the participants comprised of inactive (n = 75), active (n = 146) and trained (n = 258) individuals. Training status played a significant role in improvements in TT performance with trained individuals only seeing improvements of approximately 2% whereas individuals of lower training status demonstrated improvements as high as 6%. The change in TT performance with HIIT depended on the duration but not the intensity of the interval work-bout. There was a dose-response relationship with the number of HIIT sessions, training weeks and total work with changes in TT performance. However, the dose-response was not present with SIT. CONCLUSION: Optimization of interval training programs to produce TT performance improvements should be done according to training status. Our analysis suggests that increasing interval training dose beyond minimal requirements may not augment the training response. In addition, optimal dosing differs between high intensity and sprint interval programs.

Effect of High-Intensity Interval Training Versus Sprint Interval Training on Time-Trial Performance: A Systematic Review and Meta-analysis.

BACKGROUND: Two forms of interval training commonly discussed in the literature are high-intensity interval training (HIIT) and sprint interval training (SIT). HIIT consists of repeated bouts of exercise that occur at a power output or velocity between the second ventilatory threshold and maximal oxygen consumption (VO2max). SIT is performed at a power output or velocity above those associated with VO2max. OBJECTIVE: The primary objective of this study is to systematically review published randomized and pair-matched trials to determine which mode of interval training, HIIT versus SIT, leads to a greater improvement in TT performance in active and trained individuals. The second objective of this review is to perform a subgroup analysis to determine if there is a distinction between HIIT programs that differ in work-bout duration. DATA SOURCES: SPORTDiscus (1800-present) and Medline with Full Text (1946-present) were used to conduct a systematic literature search. STUDY SELECTION: Studies were selected for the review if they met the following criteria: (1) individuals (males and females) who were considered at least moderately trained (~ 3-h per week of activity) as specified by the authors of the included studies; (2) between the ages of 18 and 45 years; (3) randomized or pair-matched trials that included a HIIT and a SIT group; (4) provided detailed information about the interval training program; (5) were at least 2 weeks in duration; (6) included a TT test that required participants to complete a set distance. RESULTS: A total of 6 articles met the inclusion criteria for the subjective and objective analysis. The pooled analysis was based on a random-effects model. There was no difference in the change in TT performance when comparing all HIIT versus SIT (0.9%; 90% CI - 1.2-1.9%, p = 0.18). However, subgroup analysis based on duration of work interval indicated a 2% greater improvement in TT performance following long-HIIT (≥ 4 min) when compared to SIT. There was no difference in change in VO2max/peak oxygen consumption (VO2peak) between groups. There was a moderate effect (ES = 0.70) in favor of HIIT over SIT in maximal aerobic power (MAP) or maximal aerobic velocity (MAV). CONCLUSION: The results of the meta-analysis indicate that long-HIIT may be the optimal form of interval training to augment TT performance. Additional research that directly compares HIIT exercise differing in work-bout duration would strengthen these results and provide further insight into the mechanisms behind the observed benefits of long-HIIT.

Polarized vs. Threshold Training Intensity Distribution on Endurance Sport Performance: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Rosenblat MA, Perrotta AS, and Vicenzino B. Polarized vs. threshold training intensity distribution on endurance sport performance: A systematic review and meta-analysis of randomized controlled trials. J Strength Cond Res 33(12): 3491-3500, 2019-The objective of this review was to systematically search the literature to identify and analyze data from randomized controlled trials that compare the effects of a polarized training model (POL) vs. a threshold training model (THR) on measurements of sport performance in endurance athletes. This systematic review and meta-analysis is registered with PROSPERO (CRD42016050942). The literature search was performed on November 6, 2016 and included SPORTDiscus (1800-present), CINAHL Complete (1981-present), and Medline with Full Text (1946-present). Studies were selected if they included: random allocation, endurance-trained athletes with greater than 2 years of training experience and VO2max/peak >50 ml·kg·min, a POL group, a THR group, assessed either internal (e.g., VO2max) or external (e.g., time trial) measurements of endurance sport performance. The databases SPORTDiscus, Medline and CINAHL yielded a combined 329 results. Four studies met the inclusion criteria for the qualitative analysis, and 3 for the meta-analysis. Two of the 4 studies included in the review scored a 4/10 on the PEDro Scale and 2 scored a 5/10. With respect to outcome measurements, 3 studies included time-trial performance, 3 included VO2max or VO2peak, 2 studies measured time-to-exhaustion, and one study included exercise economy. There was sufficient data to conduct a meta-analysis on time-trial performance. The pooled results demonstrate a moderate effect (ES = -0.66; 95% CI: -1.17 to -0.15) favoring the POL group over the THR group. These results suggest that POL may lead to a greater improvement in endurance sport performance than THR.

Physiotherapists supporting self-management through health coaching: a mixed methods program evaluation.

PURPOSE: To evaluate a program in support of chronic disease self-management (CDSM) that is founded on a health coaching (HC) approach, includes supervised exercise and mindfulness-based stress reduction components and is delivered within a private practice physiotherapy setting. METHODS: An explanatory mixed method design, framed by theory-based program evaluation, was employed to evaluate an eight-week group-based program. Standardized self-rated and performance measures were evaluated pre- and post intervention. Additionally, participant focus groups were conducted following the intervention period. An inductive thematic approach was undertaken to analyze the qualitative data. FINDINGS: Seventeen participants (N = 17) completed the study. Improvements were seen in both self-report and performance outcomes. Participants explained how and why they felt the program was beneficial. Six themes were generated: (1) group dynamic; (2) learning versus doing; (3) holism and comprehensive care; (4) self-efficacy and empowerment; (5) previous solutions versus new management strategies; and (6) healthcare provider support. CONCLUSIONS: This study established that a group program in support of CDSM founded on a HC approach demonstrated potential value from participants as well as favorable outcomes. A pragmatic randomized control trial is required to determine efficacy of this intervention.