Effect of acute high-intensity interval exercise on a mouse model of doxorubicin-induced cardiotoxicity: a pilot study.

BACKGROUND: It is unknown whether high-intensity interval exercise (HIIE) may potentiate or attenuate the cardiotoxic effect of chemotherapy agents such as doxorubicin (DOX) when performed shortly after treatment. The study aimed to investigate the effect of acute HIIE on cardiac function and structure performed either 1, 2 or 3 days after DOX injection in an animal model. METHODS: Female C57bl/6 mice (n = 28), 70 days old, received a bolus 20 mg/kg intravenous tail vein DOX injection. Three exercise groups performed 1 HIIE session (16 sets of 1 min at 85-90% of peak running speed) at 1 (n = 7), 2 (n = 7), and 3 days (n = 8) following the DOX injection. A sedentary (SED) group of mice (n = 6) did not exercise. Animals underwent echocardiography under light anesthesia (isoflurane 0.5-1%) before and 7 days after the DOX injection. Animals were sacrificed on day 9 and hearts were collected for morphometric and histological analysis. RESULTS: Animals exercising on day 3 had the smallest pre-post reduction in left ventricular fractional shortening (LVFS) (MΔ= -1.7 ± 3.3; p = 0.406) and the SED group had the largest reduction (MΔ=-6.8 ± 7.5; p = 0.009). After reclassification of animals according to their exercise compliance (performing > 8/16 of high-intensity bouts), LVFS in compliant mice was unchanged over time (LVFS MΔ= -1.3 ± 5.6; p = 0.396) while non-compliant animals had a LVFS reduction similar to sedentary animals. There were no significant differences in myocardial histology between groups. CONCLUSIONS: In this pilot murine study, one single HIIE session did not exacerbate acute doxorubicin-induced cardiotoxicity. The timing of the HIIE session following DOX injection and the level of compliance to exercise could influence the negative impact of DOX on cardiac function.

A polyphenol-rich cranberry supplement improves muscle oxidative capacity in healthy adults.

Cranberries are rich in polyphenols, have a high antioxidant capacity, and may protect against exercise-induced free radical production. Mitochondria are known producers of free radical in skeletal muscle, and preventing overproduction of radicals may be a viable approach to improve muscle health. This stud aimed to investigate the effect of a polyphenol-rich cranberry extract on muscle oxidative capacity and oxygenation metrics in healthy active adults. 17 participants (9 males, 8 females) were tested at: i) baseline, ii) 2 hours following an acute CE dose (0.7 g/kg of body mass), and iii) after 4 weeks of daily supplement consumption (0.3 g/kg of body mass). At each time point, muscle oxygen capacity was determined using near-infrared spectroscopy to measure the recovery kinetics of muscle oxygen consumption following a 15-20 s contraction of the vastus lateralis. Cranberry supplementation over 28 days significantly improved muscle oxygen capacity (k-constant, 2.8 ± 1.8 vs. 3.9 ± 2.2; p = 0.02). This was supported by a greater rate of oxygen depletion during a sustained cuff occlusion (-0.04 ± 0.02 vs. -0.07 ± 0.03; p = 0.02). Resting muscle oxygen consumption was not affected by cranberry consumption. Our results suggest that cranberry supplementation may play a role in improving mitochondrial health, which could lead to better muscle oxygen capacity in healthy active adult populations. The study protocol was registered with ClinicalTrials.gov (#NCT06186297).

The Transtheoretical model's processes of change in the heart of a physical activity intervention: A series of n-of-1.

The objectives were a) to test whether a Processes of Change (POC)-personalized Transtheoretical model (TTM)-based intervention could increase physical activity (PA) among inactive adults, and b) to examine whether the intervention increased the level of TTM theoretical constructs. The following hypotheses were formulated: 1) PA levels will be significantly higher during and after the intervention in comparison to baseline measures; 2) the level of targeted POCs will increase during the intervention; 3) non targeted POCs will stay stable, and 4) self-efficacy and decisional balance levels will increase during the intervention. A series of N-of-1 with A (1 to 2-week)-B(10-week)-A'(2-week) design were conducted with 12 inactive adults. Behavioral counselors used behavior change techniques to target TTM constructs and supervise PA. Interventions were individualized based on the 5 POCs with the lowest pre-intervention level. Device-based and subjective PA along with TTM measures were collected weekly online. PA data were analyzed with piecewise linear models. A visual analysis was run to examine the TTM constructs. Device, self-reported and TTM data were available for five, seven and five participants, respectively. A significant self-reported PA increase for six participants was found during the phase B and A2. A significant device-measured PA increase was observed in two participants during the study. A substantial increase of targeted POC from baseline for all participants with available data was observed. This study provides the first evidence of behavioral and psychological effects of a POC-personalized TTM-based intervention in inactive adults.

Body Composition and Maximal Strength of Powerlifters: A Descriptive Quantitative and Longitudinal Study.

The purpose of this study was to present the relationships between maximal strength and body composition and to conduct yearly follow-ups presenting the chronic effects of maximal strength training on body composition. Thirty-four (age = 28.8 ± 8.7 yrs) classic powerlifters (M = 21; F = 13) completed at least one Dual-Energy X-Ray Absorptiometry (DXA) 43.97 ± 23.93 days after a sanctioned international powerlifting federation affiliate competition (Squat + Bench Press + Deadlift = Total (kg)). In addition, thirteen subjects (n = 13) completed at least one yearly follow up. Paired sample T-Tests and simple linear regressions were performed to determine significant effects on body composition and maximal strength measures. Prediction formulas were obtained as follows: Bone Mineral Content (BMC) (g) = 3.39 * Total (kg) + 1494.78 (r = 0.84; p < 0.000; SEE = 348.05); Bone Mineral Density (BMD) (g/cm3) = 0.000390 * Total (kg) + 1.115 (r = 0.71; p < 0.000; SEE = 0.062); Total (kg) = 10.84 * Lean Body Weight (LBW) (kg) - 154.89 (r = 0.90; p < 0.000; SEE = 70.27); Total (kg) = 22.74 * Relative LBW (kg/m) - 306.66 (r = 0.92; p < 0.000; SEE = 64.07). Significant differences were observed in BMD (+1.57 ± 1.55%; p = 0.018; ES = 0.22), between measures one and two (333.7 ± 36.3 days apart) as well as LBW (-2.95 ± 3.82%; p = 0.049; ES = 0.16), and Body Fat Percentage (+2.59%; p = 0.029; ES = 0.20) between measures two and three (336 ± 13.3 days apart). Thus, maximal strength can be used to predict BMC and BMD, while LBW can be used to predict maximal strength. As well, consistent powerlifting practice can increase BMD in adults.

Wrist-worn devices for the measurement of heart rate and energy expenditure: A validation study for the Apple Watch 6, Polar Vantage V and Fitbit Sense.

The purpose of this study was to investigate the accuracy of 3 recently released wrist-worn devices (Apple Watch 6, Polar Vantage V and Fitbit Sense) for heart rate and energy expenditure during various activities. The study population consisted of 60 young healthy individuals (30 men and 30 women; age: 24.9 ± 3.0 years, BMI: 23.1 ± 2.7 kg/m2). Heart rate and energy expenditure were measured using the Polar H10 and Metamax 3B, respectively (reference measures) as well as with the 3 wrist-worn devices during 5 different activities (sitting, walking, running, resistance exercises and cycling). The Apple Watch 6 displayed the highest level of accuracy for heart rate measurement with a coefficient of variation (CV) (%) of less than 5% for all 5 activities, whereas the Polar Vantage V and the Fitbit Sense presented various degrees of accuracy (from high to poor accuracy) dependent on the activity (CVs between 2.44-8.80% and 4.14-10.76%, respectively). As for energy expenditure, all 3 devices displayed poor accuracy for all 5 physical activities (CVs between 14.68-24.85% for Apple Watch 6, 16.54-25.78% for Polar Vantage V and 13.44-29.66% for Fitbit Sense). Results of the present study indicate that the Apple Watch 6 was the most accurate for measuring heart rate across all 5 activities, whereas variable levels of accuracy for heart rate measurement for the Polar Vantage V and the Fitbit Sense were observed depending on the activity. As for energy expenditure, all 3 devices showed poor accuracy during all activities.Highlights The Apple Watch 6 was the most accurate for measuring heart rate, whereas the Polar Vantage V and Fitbit Sense showed variable results dependent on the activityThe Apple Watch 6, Polar Vantage V and Fitbit Sense showed poor accuracy for energy expenditure during 5 different physical activitiesHealthcare care professionals, athletes/coaches and the general population may want to proceed with caution on the clinical utility of energy expenditure of these devices during the implementation of an exercise training or nutritional programme.

Cranberry supplementation improves physiological markers of performance in trained runners.

PURPOSE: Cranberries have the highest polyphenol and antioxidant capacity among fruits and vegetables and may protect against exercise-induced free radical production, consequently improving performance. This study aimed to investigate the effect of polyphenol-rich cranberry extract (CE) on time-trial performance and lactate response following exercise. METHODS: A total of 14 trained runners were tested at i) baseline, ii) 2 h following an acute CE dose (0.7 g/kg of body mass), and iii) 4 weeks after daily supplement consumption (0.3 g/kg of body mass). At each time point, runners performed a 1500-m race followed by a 400-m race where the live vastus lateralis oxygenation changes were determined by near-infrared spectroscopy and blood lactate was measured at rest and 1 and 3 min after each trial. The Shapiro-Wilk test and repeated-measures analysis of variance were used to establish significance (P <0.05). RESULTS: Cranberry supplementation over 28 d improved aerobic performance during the 1500-m time trial, whereas the acute dose had no effect. More specifically, muscle reoxygenation rates were significantly faster after 28 d compared to baseline (P = 0.04; η² = 0.29), and a trend towards slower deoxygenation rate was observed (P = 0.13; η² = 0.20). Chronic CE consumption also buffered the post-exercise lactate response for the 400-m race (P = 0.01; η² = 0.27), while no effects were seen for the longer race. CONCLUSION: Our results suggest that cranberry supplementation may have ergogenic effects, as it improves physiological markers of performance during short- and long-distance running.

Assessment of Training Load, Sleep, Injuries, and Operational Physical Performance During Basic Military Qualification.

INTRODUCTION: Optimizing training load (TL) and sleep is essential to maximize physical performance and prevent musculoskeletal injuries (MSKIs) for Canadian forces recruits during the 10-week basic military qualification (BMQ) course. The purpose of this study was to assess the TL, sleep duration, the occurrence of MSKIs during the BMQ, and the operation fitness performance during the BMQ. MATERIALS AND METHODS: Forty Canadian recruits, eight females and 32 males, (age 24 ± 5 years; height 176.4 ± 10.4 cm), were monitored with an accelerometer (GENEActiv) on their wrist between weeks 1 and 9 to evaluate the TL and sleep duration. During weeks 2 and 10, the recruits completed an operational fitness evaluation. Injury surveillance was performed over 10 weeks. RESULTS: TL intensity was significantly different (P = 0.0001) from week to week. The weekly average total time of moderate and vigorous physical activity was 189.7 ± 48.1 min and 44.7 ± 15.2 min, respectively. The average sleep duration was 5.4 ± 0.4 h per night and decreased to 4.2 h ± 0.4 during field exercises. A significant difference in sleep duration was observed between recruits with and without a MSKI. The recruits accumulated a total of 95 days under medical restrictions with an average of 3.8 consecutive days. The VO2peak estimated from the Fitness for Operational Requirements of Canadian Armed Forces Employment job-based simulation test significantly improved from weeks 2 to 10 (pre, 47.1 ± 6.3; post: 50.2 ± 5.8; P = 0.001). CONCLUSIONS: TL is of high magnitude and varies from week to week. The reported mean sleep duration per week may perhaps negatively impact the occurrence of MSKI. No significant improvement was detected in operational fitness by the end of the BMQ.

Static Postural Control Deficits in Adults with Myotonic Dystrophy Type 1, Steinert Disease.

BACKGROUND: Myotonic dystrophy type 1 (DM1) is characterized by progressive and predominantly distal muscle atrophy and myotonia. Gait and balance impairments, resulting in falls, are frequently reported in this population. However, the extent to which individuals with DM1 rely more on a specific sensory system for balance than asymptomatic individuals (AI) is unknown. OBJECTIVE: Evaluate postural control performance in individuals with DM1 and its dependence on vision compared to AI. METHODS: 20 participants with DM1, divided into two groups based on their diagnosis, i.e. adult and congenital phenotype, and 12 AI participants were recruited. Quiet standing postural control was assessed in two visual conditions: eyes-open and eyes-closed. The outcomes measures were: center of pressure (CoP), mean velocity, CoP range of displacement in anteroposterior and mediolateral axis, and the 95% confidence ellipse's surface. Friedman and Kruskal-Wallis analysis of variance were used to compare outcomes between conditions and groups, respectively. RESULTS: Significant group effect and condition effect were observed on postural control performance. No significant difference was observed between the two DM1 groups. The significant differences observed between the AI group and the two DM1 groups in the eyes-open condition were also observed in the eyes-closed condition. CONCLUSIONS: The result revealed poorer postural control performance in people with DM1 compared to AI. The DM1 group also showed similar decrease in performance than AI in eyes-closed condition, suggesting no excessive visual dependency.

Secular trends of cardiorespiratory fitness in children and adolescents over a 35-year period: Chronicle of a predicted foretold.

Background: In the context of concerns regarding the cardiorespiratory fitness (CRF) of youth populations, the aims of this study were: (1) to update reference values for the VO2max for school-aged Canadians and (2) to document secular trends in CRF after a 35-year interval. Methods: Between September 2014 and April 2017, the CRF of 3725 students (53.2% boys; 6.0 to 17.9 yrs) was determined using the 20-m shuttle run test. The sample was collected in 36 different schools from six cities of Québec (Canada). Results: Median values of VO2max decreased with age in both sexes (p ≤ 0.05). By the age of 10, more than 20% of boys showed VO2max values below the recommended value (42 ml·kg-1·min-1). At the age of 17, that proportion reached 56.8%. A similar proportion of 12 yrs girls (20%) were under the recommended minimal value (37 ml·kg-1·min-1) and that value reached 69.9% at the age of 17. Compared to 1982, the VO2max at age 17 has declined by 18% for boys and 12% for girls. The situation is worse in terms of functional capacity (number of stages completed) with an overall decrease of more than 30%. Conclusion: This study demonstrates that, compared to data obtained using the same methodology 35 years ago, the CRF and functional capacity of children and adolescents has declined to levels that should raise concerns from a public health perspective. Thus, the development of strategies to promote a physically active lifestyle in youth is more relevant than ever.

Ice Hockey Goaltender Physiology Profile and Physical Testing: A Systematic Review and Meta-Analysis.

This review aims to 1) be the first systematic review and meta-analysis of the literature examining the physiology and assessment of goaltenders, and 2) present a physiological profile of ice-hockey goaltenders. It will 1) highlight physiological differences between goaltenders and players at other positions, 2) determine strengths and weaknesses of ice hockey goaltenders, and 3) offer possible guidelines for strength and conditioning coaches. Six electronic databases were systematically searched in October 2019 using the PRISMA model. A total of twelve scientific articles published in peer-reviewed journals were included. Professional male (PM) goaltenders had the following profile for age (A) 26.8 ± 2.5 years, body weight (BW) 85.64 ± 3.79 kg, height (H) 184.38 ± 2.79 cm, body fat % (BF%) 11.9 ± 2.22, VO2max 49.9 ± 4.45 ml/kg/min, anaerobic power (AP) 12.78 ± 1.63 W/kg, and combined hand grip strength (GS) 120.7 ± 15 kg. Amateur male (AM) goaltenders presented the following: A: 18.2 ± 0.75, BW: 83.85 ± 4.51, H: 184.96 ± 2.06, BF%: 10.51 ± 1.61, VO2max: 55.73 ± 4.57, AP: 10.9 ± 1.2 and GS: 109.08 ± 14.06. Amateur female (AF) goaltenders presented the following: A: 21.04 ± 1.84, BW: 63.4 ± 5.14, H: 164.86 ± 5.73, BF%: 22.12 ± 2.27 and VO2max: 42.84 ± 3.59. Overall, PM goaltenders are heavier, have a higher BF%, and exhibit greater GS and abdominal muscular endurance than AM, while AM goaltenders are heavier, taller, leaner, and can generate greater lower-body muscular power than AF goaltenders. In the current literature, there were a small number of studies on women players and a lack of distinction between player position in reported results. Specific physiological assessments during NHL Combines should be developed for goaltenders in accordance with their specific positional demands.

Psychological Status During and After the Preparation of a Long-distance Triathlon Event in Amateur Athletes.

Preparation for an endurance event among amateur athletes requires a major commitment on their part. Knowing amateur athletes' psychological characteristics during a training period should be a priority for coaches and athletes. The aim of our longitudinal study was to characterize the psychological profile of amateur athletes over a training period of six months prior to and after a long-distance triathlon. Thirty-two amateur athletes (13 females; 19 males; 1.5±1.3 years of experience) were recruited for this observational study. All participants (39±9.9 years old; weighs 73±12.9 kg; measure 172±10.2 cm) underwent a physical fitness assessment pre- and post 6-months of training, a monthly psychological questionnaire battery assessing mood, positive and negative affect, passion and motivation and, for some participants (n=5), an interview post event. Positive emotions increased until the sixth month, from 38.1±22.0 to 54.3±7.2 (Z=3.49, p<0.001, r=0.80). Participants were more harmonious (29.0±3.0) than obsessive (13.0±1.0) with their triathlon's passion (Z=4.91, p<0.001, r=0.85). Participants felt a high level of intrinsic motivation (15.9±1.76) and a low level of external motivation (4.9±1.08) about their triathlon training (p<0.05). The vigor score is the only sub scale that significantly changed from the 1st to the 6th month of training, and ranged between 21.4±10.6 and 28.1±4.1 (Z=2.0, p=0.046, r=0.46). This longitudinal observational study is the first to have explored athletes' psychological and emotional parameters over a training period of six months prior to a long-distance triathlon event and one month after. Thus, specific interventions and mental training can be structured around these important milestones.

Maximal Oxygen Consumption Requirements in Professional North American Ice Hockey.

ABSTRACT: Ferland, P-M, Marcotte-L'Heureux, V, Roy, P, Carey, V, Charron, J, Lagrange, S, Leone, M, and Comtois, AS. Maximal oxygen consumption requirements in professional North American ice hockey. J Strength Cond Res 35(4): 1586-1592, 2021-This study was designed to measure preseason on-ice relative V̇o2max of professional ice-hockey players (n = 101 National Hockey League [NHL], 42 American Hockey League [AHL], 4 East Coast Hockey League [ECHL], and 15 Canadian Hockey League [CHL]) throughout 17 years and compare it between generations, league level, and position, and to verify if it was related to season and NHL career statistics. Relative V̇o2max was measured on ice with a portable metabolic analyzer (K4b2, Cosmed, Rome) with full hockey equipment, except for the helmet with either the Skating Multistage Aerobic Test or the 30-15 intermittent ice test tests. Relative V̇o2max results from both tests were compared between players of the same generation with an independent-samples T-test and were not significantly different. A one-way analysis of variance and post hoc pairwise tests were performed to detect significant differences between groups. Pearson correlations (two-tailed) were also performed between selected variables. All statistical significance was set at p < 0.05. Results show that there are no significant differences for relative V̇o2max between generations (2001-2003 vs. 2006 vs. 2015-2017), league level (NHL vs. AHL vs. ECHL vs. CHL), and position (winger, center, and defense), other than the ECHL being lower. There are also no significant relationships between V̇o2max values and hockey season and NHL career statistics. Thus, the results show that there is a minimal relative V̇o2max requirement to play North American ice hockey at the elite level (55.9 ± 5.2 ml·kg-1·min-1; n = 162). Future research should be directed toward comparing V̇o2max of elite and amateur ice-hockey players to confirm the minimal relative V̇o2max requirement to play North American ice hockey at the elite level.

Remote Ischemic Preconditioning Does Not Improve the Six Minutes Walk Test Performance in Chronic Heart Failure Patients: a Randomised Pilot Trial.

Cycles of ischemia and reperfusion induced with a pressure cuff on a skeletal muscle, also know as remote ischemic preconditioning (RIPC), appears to improve performance in different time-trial events in healthy individuals. Our primary goal was to assess the effect of RIPC in heart failure (HF) patients' functional capacity using the six-minute walk test (6MWT). A randomized crossover design comparing RIPC (4 × five-minutes of upper arm ischemia) to the SHAM procedure was done in 15 patients prior to a 6MWT. The primary outcome measure was the total distance walked in a standardized 6MWT (20m corridor). Metabolic and hemodynamic responses were measured using gas exchange analysis with a portable metabolic analyzer and peripheral skeletal muscle oxygen saturation (smO2) with near-infrared spectroscopy. The total distance travelled during 6MWT was not significantly different between the RIPC (347 ± 63 m) and the SHAM procedure (352 ± 65 m; p = 0.514). Relative oxygen uptake did not change when comparing interventions: 10.26 ± 2.01 ml/kg/min vs 10.69 ± 2.51 ml/kg/min (RIPC vs SHAM, respectively, p = 0.278). As well, no significant differences were observed for heart rate, respiratory exchange ratio, smO2, and ventilation. Even though HF patients tolerated well the RIPC intervention, it did not provide any significant improvement in functional capacity and other physiological parameters in our sample of patients.

Assessment of On-Ice Oxygen Cost of Skating Performance in Elite Youth Ice Hockey Players.

ABSTRACT: Allisse, M, Bui, HT, Desjardins, P, Léger, L, Comtois, AS, and Leone, M. Assessment of on-ice oxygen cost of skating performance in elite youth ice hockey players. J Strength Cond Res 35(12): 3466-3473, 2021-The purpose of this study was to evaluate the robustness of equations to predict the oxygen requirement during different skating circumstances commonly found in ice hockey game situations (skating forward, backward, with and without controlling a puck, during cornering and stops and starts). Twenty-four male elite ice hockey players from 3 categories (pee-wee, bantam, and midget) participated in this study. Anthropometric measurements were taken, and 4 different on-ice high-intensity and short-duration tests were performed. Execution time, heart rate, oxygen uptake, skating strides, and a skating efficiency index were measured for each test. A regression equation was calculated for each of the 4 tests providing an estimation of oxygen cost. Correlation coefficients ranged from 0.91 to 0.93, and SEE was between 4.5 and 8.4%, indicating that the precision of the regression algorithms was excellent. The results also suggest that execution time alone, which is the traditional manner to measure skating performance, is a bad estimator of oxygen uptake requirement for this kind of effort (average common variance <11%). Furthermore, age proved to be a determining factor with younger players showing an overall lower level of skating efficiency compared with older players. In addition, the introduction of a skating index also helps to better determine which factor of performance needs to be improved. Using simple and easy-to-measure variables, coaches will be able to obtain information that will allow them to intervene more precisely on the training parameters that will optimize the individual on-ice performance of their players.

Updating the Skating Multistage Aerobic Test and Correction for V[Combining Dot Above]O2max Prediction Using a New Skating Economy Index in Elite Youth Ice Hockey Players.

Allisse, M, Bui, HT, Léger, L, Comtois, A-S, and Leone, M. Updating the skating multistage aerobic test and correction for V[Combining Dot Above]O2max prediction using a new skating economy index in elite youth ice hockey players. J Strength Cond Res 34(11): 3182-3189, 2020-A number of field tests, including the skating multistage aerobic test (SMAT), have been developed to predict V[Combining Dot Above]O2max in ice hockey players. The SMAT, like most field tests, assumes that participants who reach a given stage have the same oxygen uptake, which is not usually true. Thus, the objectives of this research are to update the V[Combining Dot Above]O2 values during the SMAT using a portable breath-by-breath metabolic analyzer and to propose a simple index of skating economy to improve the prediction of oxygen uptake. Twenty-six elite hockey players (age 15.8 ± 1.3 years) participated in this study. The oxygen uptake was assessed using a portable metabolic analyzer (K4b) during an on-ice maximal shuttle skate test. To develop an index of skating economy called the skating stride index (SSI), the number of skating strides was compiled for each stage of the test. The SMAT enabled the prediction of the V[Combining Dot Above]O2max (ml·kg·min) from the maximal velocity (m·s) and the SSI (skating strides·kg) using the following regression equation: V[Combining Dot Above]O2max = (14.94 × maximal velocity) + (3.68 × SSI) - 24.98 (r = 0.95, SEE = 1.92). This research allowed for the update of the oxygen uptake values of the SMAT and proposed a simple measure of skating efficiency for a more accurate evaluation of V[Combining Dot Above]O2max in elite youth hockey players. By comparing the highest and lowest observed SSI scores in our sample, it was noted that the V[Combining Dot Above]O2 values can vary by up to 5 ml·kg·min. Our results suggest that skating economy should be included in the prediction of V[Combining Dot Above]O2max to improve prediction accuracy.

Efficiency of the Wilks and IPF Formulas at Comparing Maximal Strength Regardless of Bodyweight through Analysis of the Open Powerlifting Database.

The purpose of this study was to measure the efficiency of the Wilks and International Powerlifting Federation (IPF) Formulas at comparing powerlifting performance (total) between weight classes of the same sex (men and women) and division (classic and equipped) in order to determine the champion of champions. The Open Powerlifting database was downloaded (June 21st, 2019), filtered (Python) and analyzed (IBM SPSS). Single factor ANOVA revealed that the total (kg) was able to compare 3 out of the 98 weight class comparison possibilities (3.1%), the total ratio was able to compare 5 of the 98 weight class comparison possibilities (5.1%), the Wilks Formula was able to compare 53 of the 98 weight class comparison possibilities (54.1%) and that the IPF formula was able to compare 51 of the 98 weight class comparison possibilities (52%). Making the Wilks slightly more efficient than the IPF Formula (54.1% > 52%) at determining the champion of champions. Results also show that the IPF Formula is more efficient at comparing women's weight classes and that the Wilks Formula is more efficient at comparing men's weight classes, for both divisions. Results could not validate the IPF's decision to replace the Wilks by the IPF Formula. Subjects' performances (kg, ratio, % of the event on the total, Wilks and IPF points) presented for each weight class per sex and division coming from a total of 26,472 open powerlifters could be utilized by practitioners. Further research should be directed towards updating the constants of both formulas.

Physiological Responses to Repeated Running Sprint Ability Tests: A Systematic Review.

The purpose of this study was to review acute physiological responses induced by repeated running sprint ability (RRSA) tests that could serve as references for practitioners utilising repeated sprints as a performance measure with athletes. This research was conducted following the PRISMA methodology. The systematic search was conducted in November 2019 and yielded 26 different scientific articles. Only peer-reviewed full-text article were included as abstracts are too short to allow proper explanation of the RRSAT methodology that was employed. According to the present literature, practitioners should use the following assessments: the 6×40m RRSA protocol with one Change of Direction (COD) (20+20 m with a 180° COD) and 25s of passive recovery between sprints with soccer players; the Intensive Repeated Sprint Ability (IRSA) test with men basketball players; the Futsal Intermittent Endurance Test (FIET) with futsal players; the Repeated Shuttle Sprint Test (RSST) with men handball players; and the Multiple Repeated Sprint Ability test for Badminton players (MRSAB). The present review should serve as a reference standard for RRSA tests. Further research should be directed towards creating and validating more specific RRSA tests protocols to each sports physiological and physical demands.

The Relationship Between Physical Characteristics and Maximal Strength in Men Practicing the Back Squat, the Bench Press and the Deadlift.

This study was designed to quantify the relationships between physical characteristics and maximal strength in the back squat, the bench press and the deadlift on powerlifters and football players. Eighteen male junior drug-tested classic powerlifters and seventeen NCAA Division II American football players' anthropometric measurements were taken to compare them with maximal strength results from either a powerlifting meet or testing from their supervised strength and conditioning program. Pearson's bivariate correlations analysis revealed (statistical significance was set at p<0.05) that individuals with a greater (Wilks points) back squat, generally presented a higher Bodyweight (BW) (r=0.37), Body Mass Index (BMI) (r=0.45), Bodyfat Percentage (BF%) (r=0.36), Hip (r=0.41), Waist (r=0.35) and Torso (r=0.41) Circumference (C), Hip C/Height (r=0.46), Waist C/Height (r=0.39) and Torso C/Height (r=0.45) ratios. The individuals with a greater bench press generally presented a higher BMI (r=0.37), Lean Body Weight (LBW) (r=0.36), Hip C (r=0.39) and Hip C/Height ratio (r=0.39). On the other hand, individuals with a greater deadlift were generally older (r=0.34), shorter (r=-0.41), had shorter thighs (r=-0.52) and trunks (r=-0.36), smaller Thigh Length (L)/Height ratio (r=-0.44), Waist C/Hip C (r=-0.41) and Thigh L/Lower Leg L (r=-0.53) ratios, but a higher Lower Leg L/Height ratio (r=-046). The results of this study should be utilized by strength and conditioning coaches to deepen their comprehension of their athletes' physical characteristics in order to help them develop strength through their advantages. Further research should focus on evaluating how physical characteristics affect performance in different squat, bench, and deadlift stances.

Contrast Training Generates Post-Activation Potentiation and Improves Repeated Sprint Ability in Elite Ice Hockey Players.

The purpose of this study was to measure the generating effects of Contrast Training (CT) on 6-hour post-activation potentiation (PAP) and its influence on jumping and on on-ice repeated sprint performance in ice hockey players. Forty-one participants were divided in two groups: experimental (EG) and control group (CG). The EG followed the CT PAP protocol which consisted of 5 sets of 5 half inertia back squat superset with 6 squat jumps. The effects of PAP were measured with the vertical countermovement jump (CMJ), stationary broad jump (BJ) and 9 repeated on ice 40-meter maximal sprints with hockey equipment. Results showed that the PAP generated by the CT protocol had no significant impact (p ≥ 0.05) on CMJ, BJ, blood lactate concentration, heart rate peak and rated perceived exertion as EG and CG group presented no significant differences in improvement. However, results show that there was a significant improvement (p < 0.05) for the EG in the total sprint time (-5.5 ± 2.6%; 56.2 ± 4.7 to 53.1 ± 3.9sec) mean sprint speed (+5.9 ± 3.0%; 6.4 ± 0.5 to 6.8 ± 0.5m/s) and in 1st sprint speed (+7.4% ± 5.9; 7.3 ± 0.7 to 7.8 ± 0.6m/s), but not for the CG (-1.4 ± 5.1%; 58.0 ± 5.4 to 57.2 ± 6.4sec), (+1.7 ± 5.1 %; 6.3 ± 0.6 to 6.4 ± 0.6m/s) and (+1.9 ± 7.7%; 6.9 ± 0.7 to 7.0 ± 0.7m/s) respectively. Thus, results show that the CT protocol utilized in this study generated PAP which had an acute effect on the on-ice hockey repeated sprint test performance. Therefore, CT could be utilized punctually to improve repeated sprint performance of elite hockey players as it could potentially help create odd man rushes during games.