A Half-Century of Evidence-Based Cardiac Rehabilitation: A Historical Review.

OBJECTIVE: To review the achievements of cardiac exercise rehabilitation programs retrospectively and to identify continuing challenges to their success. METHODS: A review of files accumulated while working with the Toronto Rehabilitation Center, updated by articles identified by PUB-MED, OVID, and Google Scholar through February 2019. RESULTS: After the early lead of Israeli physicians, cardiac rehabilitation began in Ontario during the 1960s and quickly attracted a large case load. Recurrence rates of the patients recruited were low relative to those receiving standard medical treatment, even after allowing for differences in risk factors at entry to programs. Controlled trials began but were individually of insufficient in size to show a significant reduction in recurrences or mortality. Subsequently, multiple meta-analyses demonstrated a 20% to 25% reduction of all-cause and cardiac mortality over the first few years of follow-up in patients who persisted with their rehabilitation. Compliance continued a problem at many centers, but special features of the Toronto cardiac rehabilitation program sustained a compliance of 82.8% over 3 years. Although vigorous exercise increased the immediate risks of a recurrence 5- to 10-fold, this was more than offset by the long-term benefits of enhanced physical condition, and cardiac deaths were a rarity during either supervised or home-based exercise sessions. About a half of patients developed a depression immediately after infarction, but if encouraged to persist with prescribed exercise, their quality of life progressively improved. Among the wide variety of mechanisms underlying the benefits of exercise, gains of aerobic power seemed particularly important. With sustained training, the physical condition of some younger patients progressed to the point of participating successfully in marathon events. Older patients also benefited from sustained training, but for them, optimal results were likely associated with less rigorous physical demands. CONCLUSIONS: Research conducted in Toronto and elsewhere has established the benefits of exercise-centered cardiac rehabilitation. However, there remains a need to define the optimum timing of program onset, and the frequency, intensity, and duration of supervised training sessions. Return to blue-collar occupations also needs to be boosted, and the limited participation of eligible patients in available programs remains a continuing challenge.

Observing Ramadan and sleep-wake patterns in athletes: a systematic review, meta-analysis and meta-regression.

OBJECTIVE: To evaluate the effect of observing Ramadan on athletes' sleep patterns. DESIGN: Systematic review and meta-analysis. DATA SOURCES: The entire content of PubMed/MEDLINE and Web of Science. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Single-group, prepost and cross-over design studies conducted in athletes aged ≥18 years, training at least twice a week and published in English before 12 July 2018 were included. Studies assessing sleep quantity, quality, daytime sleepiness and/or daily naps based on objective or subjective methods were deemed eligible. STUDY APPRAISAL: The methodological quality was assessed using 'QualSyst'. RESULTS: Of 13 selected articles, 7 were of strong quality, 3 were moderate and 3 were weak. 11 studies evaluated total sleep time (TST); this decreased during Ramadan in 4 studies, increased in 1 and remained unchanged in 6. Pooled TST findings indicated a moderate effect size (- 0.97, SE=0.37, 95% CI -1.69 to -0.25, t=-2.64, p=0.01) with significant heterogeneity but no publication bias. Meta-regressions showed no effects of study year, age, sample size, type of sport or competition level, but there were effects of country (with France and Tunisia being the most affected countries and Turkey the least affected, Q=32.14, p<0.0001) and study design (Q=7.74, p=0.02). Four studies measured self-reported sleep quality and it decreased in three studies. One study of sleep architecture reported more frequent waking and more light sleep during Ramadan. Daily nap duration was increased in two studies, but daytime sleepiness remained unchanged in four studies. CONCLUSION: When athletes continue to train at least two times/week while observing Ramadan, TST is decreased compared with athletes' baseline levels.

Effects of Combined Balance and Plyometric Training on Athletic Performance in Female Basketball Players.

Bouteraa, I, Negra, Y, Shephard, RJ, and Chelly, MS. Effects of combined balance and plyometric training on athletic performance in female basketball players. J Strength Cond Res 34(7): 1967-1973, 2020-The purpose of this study was to examine the effect of 8 weeks combined balance and plyometric training on the physical fitness of female adolescent basketball players. Twenty-six healthy regional-level players were randomly assigned to either an experimental group (E; n = 16, age = 16.4 ± 0.5) or a control group (C; n = 10, age = 16.5 ± 0.5). C maintained their normal basketball training schedule, whereas for 8 weeks E replaced a part of their standard regimen by biweekly combined training sessions. Testing before and after training included the squat jump (SJ), countermovement jump (CMJ), drop jump (DJ), 5-, 10-, and 20-m sprints, Stork balance test (SBT), Y-balance test (YBT) and modified Illinois change of direction test (MICODT). Results indicated no significant intergroup differences in SJ and CMJ height; however, E increased their DJ height (p < 0.05, Cohens'd = 0.11). No significant intergroup differences were found for sprint performance or SBT, but dynamic YBT tended to a significant group interaction (p = 0.087, d = 0.006). Post hoc analysis also showed a significant increase of MICODT for E (Δ 6.68%, p = 0.041, d = 0.084). In summary, the addition of 8 weeks of balance and plyometric training to regular in-season basketball training proved a safe and feasible intervention that enhanced DJ height, balance, and agility for female adolescent basketball players relative to the standard basketball training regimen.

Changes in and Interactions between Physical and Mental Health in Older Japanese: The Nakanojo Study.

BACKGROUND: An age-related decrease in functional capacity is consistently reported, but it is not consistently related to a worsening of health-related quality of life (HRQOL) or psychological adjustment. A poor functional capacity and HRQOL have been associated with anxiety or depression, but the possible causal nature and direction of the relationship remain to be explored using long-term longitudinal data. OBJECTIVE: The purpose of this study was to examine age-related changes in functional capacity, HRQOL, and scores on the Hospital Anxiety and Depression Scale (HADS), and possible causal interrelationships between these variables. METHODS: Study participants were 5,124 Japanese aged ≥65 years. After the baseline study (2003), annual follow-up observations continued for 10 years. Generalized linear mixed models examined age-related changes in Barthel index (BI), Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-IC), HRQOL, and HADS. Cross-lagged effects models tested possible causal interrelationships. RESULTS: With age, functional capacity and HRQOL scores showed similar declines in both sexes. Changes in mental health, anxiety, and depression developed more slowly than decreases in physical health (BI, TMIG-IC, and physical functioning scores). Cross-lagged effects models demonstrated that functional capacity had positive effects on psychological adjustment, and that psychological adjustment had positive effects on functional capacity 5 years later. Interactions between functional capacity and psychological adjustment showed no sex differences. A decline in functional capacity negatively affected psychological adjustment, but reduced psychological adjustment had no significant impact on functional capacity 5 and 10 years later. Moreover, functional capacity and poor psychological adjustment showed no interactions in either sex. CONCLUSION: Functional capacity and mood state are interrelated. Greater function could sustain vitality and mental health, possibly reducing anxiety and depression.

Effects of a Combined Upper- and Lower-Limb Plyometric Training Program on High-Intensity Actions in Female U14 Handball Players.

PURPOSE: To analyze the effects of a 9-week plyometric training program on the sprint times (5, 10, 20, and 30 m), change-of-direction speed (modified T test and modified Illinois test), jumping (squat jump, countermovement jump, countermovement jump with arms, and horizontal 5-jump test), upper-body strength (right and left handgrip, back extensor strength, and medicine ball throw), and balance (Y and stork balance tests) of female handball players. METHODS: Athletes were randomly divided into experimental (n = 21; age = 13.5 [0.3] y) and control (n = 20; age = 13.3 [0.3] y) groups. Training exercises and matches were performed together, but the experimental group replaced a part of their normal regimen by biweekly upper- and lower-limb plyometric training. RESULTS: Both groups improved performance, but to a greater extent in the experimental group compared with controls for 20- and 30-m sprint times (Δ% = 9.6, P < .05, d = 0.557 and Δ% = 20.9, P < .001, d = 1.07, respectively), change of direction (T test: P < .01, Δ% = 14.5, d = 0.993 and Illinois test: P < .01, Δ% = 7.9, d = 0.769), vertical and horizontal jumping (P < .05), all measures of upper-limb strength (P < .001), and left-leg stork balance (P < .001, Δ% = 49.9, d = 1.07). CONCLUSIONS: A plyometric training program allows female junior handball players to improve important components of their physical performance.

Effects of plyometric jump training on the physical fitness of young male soccer players: Modulation of response by inter-set recovery interval and maturation status.

The effects of plyometric jump training on the physical fitness of male youth (age = 10-17 years) soccer players was examined in relation to inter-set recovery intervals and the maturity of the players in a single-blind, randomized-and controlled crossover trial. Jumping tests and kicking velocities were measured before (T0), after a 6 week control period (T1), after 6 weeks of plyometrics (T2), after 6 weeks of wash-out (T3), and after a further 6 weeks of plyometrics (T4). Subjects were divided into pre- and post- peak-height-velocity (PHV) groups, and were randomly assigned to 30 s or 120 s inter-set intervals during periods T2 and T4. Any changes in jumping and maximum kicking velocities during T1 and T3, had trivial effect sizes (0.01-0.15), but small to moderate improvements (effect size = 0.20-0.99) were observed in both groups during T2 and T4. Gains in pre-PHV players were similar for the two inter-set intervals, but gains in post-PHV players were greater (p < 0.05) with an inter-set recovery of 120 s than with a 30 s recovery. We conclude that plyometric jump training improves the physical fitness of adolescents, irrespective of their maturity, but that in older individuals gains are greater with a longer inter-set recovery interval.

Effects of Contrast Strength vs. Plyometric Training on Lower-Limb Explosive Performance, Ability to Change Direction and Neuromuscular Adaptation in Soccer Players.

Hammami, M, Gaamouri, N, Shephard, RJ, and Chelly, MS. Effects of contrast strength vs. plyometric training on lower-limb explosive performance, ability to change direction and neuromuscular adaptation in soccer players. J Strength Cond Res 33(8): 2094-2103, 2019-The aim was to compare the effects of 2 differing 8-week in-season strength training programs (contrast strength training [CST] vs. plyometric training [PT]) on selected performance tests (5 and 40 m sprints, S 4 × 5 m change of direction test, squat jump [SJ] and countermovement jump [CMJ], leg peak power on a cycle-ergometer force-velocity test, 1 repetition maximal half-squat, and electromyographic [EMG] activity of the vastus lateralis, vastus medialis, and rectus femoris muscles during vertical jump tests). Forty male soccer players (age = 15.8 ± 0.4 years; body mass = 58.8 ± 6.3 kg; body height = 1.74 ± 0.06 m; body fat = 10.5 ± 1.9%) were divided between a contrast strength group (CSG, n = 14), plyometric group (PG, n = 14), and control group (CG, n = 12). Both training programs enhanced sprint performance (p < 0.001 in 5 m; p ≤ 0.05 in 40 m) and change of direction test scores (p < 0.001) relative to controls. The plyometric group and CSG increased SJ height relative to the CG, with a slightly greater response in CSG compared with PG (p ≤ 0.05). Most CMJ scores increased significantly in both CSG and PG relative to the CG, with no intergroup differences in training response. Most force-velocity scores increased significantly in the CSG relative to PG and CG. The EMG parameters also increased in the CSG relative to both PG and CG. In summary, most measures of athletic performance in male soccer players were enhanced after CST and PT. However, the improvement of physical performance was better with 8 weeks of CST than with PT. Thus, coaches should be encouraged to include CST as an element of in-season conditioning.

Effects of In-Season Circuit Training on Physical Abilities in Male Handball Players.

Hermassi, S, Wollny, R, Schwesig, R, Shephard, RJ, and Chelly, MS. Effects of in-season circuit training on physical abilities in male handball players. J Strength Cond Res 33(4): 944-957, 2019-This study analyzed the effects of a resistance-type circuit training (RCT) program (30-35 minutes, performed twice a week for 10 weeks) on male handball players. Twenty-two male players were divided into experimental (E; age 20.3 ± 0.5 years) and control groups (C; age 20.1 ± 0.5 years). Measures before and after RCT included squat jump (SJ), countermovement jump (CMJ), 1 repetition maximum (1RM) of bench press, pull-over and back half-squats, throwing velocity (a 3-step running throw [RT], and a jump throw [JT]), repeated-sprint ability (six 2 × 15-m shuttle sprints with recording of best time for a single trial), anthropometric estimates of leg- and thigh-muscle volumes and mean thigh cross-sectional area (CSA), and a test of agility. The agility T-half test showed a significant interaction effect (p = 0.001; η = 0.422), with an intergroup difference in effect size (d) of 1.27 (dTG = 1.24 vs. dCG = -0.03). The SJ displayed no interaction effect. The interaction effects for half back squat (d = 2.73, η = 0.740) and CMJ (d = 3.76, η = 0.700) were large, but that for RT was smaller (η = 0.460) than that for JT (η = 0.745). The throwing velocity of C decreased for both measures, with negative effect sizes (d = -0.18 and d = -0.93, respectively). Upper-body, leg, and thigh-muscle volumes and thigh CSA increased significantly after resistance training. However, repeated-sprint parameters showed no significant changes. During the competitive season, 10 weeks of RCT with only 2 training sessions per week improved numerous measures of athletic performance in handball players, and such conditioning can be highly recommended as part of the annual training program for elite handball players.

Effects of Short-Term In-Season Weightlifting Training on the Muscle Strength, Peak Power, Sprint Performance, and Ball-Throwing Velocity of Male Handball Players.

Hermassi, S, Schwesig, R, Aloui, G, Shephard, RJ, and Chelly, MS. Effects of short-term in-season weightlifting training on the muscle strength, peak power, sprint performance, and ball-throwing velocity of male handball players. J Strength Cond Res 33(12): 3309-3321, 2019-This study analyzed the effects of in-season weightlifting training, conducted biweekly for 12 weeks. Twenty-two male handball players were divided into experimental (age: 20.3 ± 0.5 years, height: 1.85 ± 0.04 m, and body mass: 86.3 ± 9.4 kg) and control (age: 20.1 ± 0.5 years, height: 1.81 ± 0.05 m, and body mass: 83.9 ± 10.3 kg) groups, and performance was assessed before and after the intervention. Peak power was determined by a cycle ergometer force-velocity test, a vertical squat jump, and a countermovement jump. Measures of 1 repetition maximal strength included bench press, back half-squats, snatch, and clean and jerk. Handball-throwing velocity was assessed by standing, running, and jump throws. The change of direction T-half test and sprint times over 5, 15, and 30 m were recorded by paired photocells. The intraclass correlation coefficient of all parameters exceeded 0.75. Significant training effects were seen for all sprint (3/3) and throwing (3/3) measures, but only 7/14 strength parameters and 3/10 jump parameters. The largest increases of performance were for snatch (η = 0.627; d = 2.85) and 15-m sprinting (η = 0.852; d = 2.73). Countermovement jump force showed a negative response (d = -0.62). Three other parameters (V0 power for the upper and lower limbs, countermovement jump power) showed only small effect sizes (d = 0.45, d = 0.31, and d = 0.23, respectively). We conclude that 12 weeks of biweekly in-season weight training improved the peak power, maximal strength, sprinting, and throwing in handball players, but that their jump performance did not increase with this kind of intervention.

Effects of Combined Plyometric and Short Sprint With Change-of-Direction Training on Athletic Performance of Male U15 Handball Players.

Hammami, M, Gaamouri, N, Aloui, G, Shephard, RJ, and Chelly, MS. Effects of combined plyometric and short sprint with change-of-direction training on athletic performance of male U15 handball players. J Strength Cond Res 33(3): 662-675, 2019-This study examined the effects of combined plyometric and change-of-direction training (CPT) on selected measures of performance (repeated-sprint T-test [RSTT], sprint performance [5, 10, 20, and 30 m], change-of-direction tests [modified Illinois test and T-half test], squat jump, countermovement jump, countermovement jump with aimed arms 5-jump test, Y-balance test, Stork balance test, and 20-m shuttle run) in male U15 handball players. Players were randomly divided between experimental (n = 14; age: 14.5 ± 0.3 years) and control (n = 14; age: 14.6 ± 0.2 years) groups. All trial participants trained and played matches together, but for 8 weeks in the latter part of the season, the experimental group replaced the tactical part of their normal regimen by a biweekly course of CPT. This induced significant increases in sprint performance relative to controls (p = 0.006, effect size [ES] = 0.135, 8.7%; p=<0.001, ES = 0.214, 7.4%; p = 0.022, ES = 0.096, 7.2%; and p = 0.032, ES = 0.085, 8.9% over distances of 5, 10, 20, and 30 m, respectively). The modified Illinois test and T-half test also showed significant gains for experimental subjects (p < 0.025; ES = 0.205, 4.2% and p < 0.001; ES = 0.093, 5.3%, respectively), as did vertical and horizontal jumps. However, there were no significant changes of RSTT, 20-m shuttle run, or balance. Nevertheless, we conclude that the current CPT is effective in enhancing sprint performance, change-of-direction tests, and vertical and horizontal jumping and thus it can be commended to male U15 handball players as a useful option for improving important components of their physical performance.

Effects of an 8-Week In-Season Elastic Band Training Program on Explosive Muscle Performance, Change of Direction, and Repeated Changes of Direction in the Lower Limbs of Junior Male Handball Players.

Aloui, G, Hammami, M, Fathloun, M, Hermassi, S, Gaamouri, N, Shephard, RJ, and Chelly, MS. Effects of an 8-week in-season elastic band training program on explosive muscle performance, change of direction, and repeated changes of direction in the lower limbs of junior male handball players. J Strength Cond Res 33(7): 1804-1815, 2019-The aim of this study was to examine the effects of incorporating 8 weeks of biweekly lower-limb elastic band training (knee and hip extension) into the in-season regimen of junior handball players. Study participants (30 men, aged 18.7 ± 0.8 years, body mass 81.1 ± 15.4 kg, height 1.82 ± 0.06 m, body fat: 15.5 ± 5.2%) were randomly assigned between control and experimental groups. Measures obtained before and after intervention included a cycle ergometer force-velocity test, force platform determinations of squat and countermovement jump characteristics, sprint times (5 and 30 m), repeated change-of-direction (RCOD) and change-of-direction (T-half, COD) tests, 1 repetition maximum (RM) half back squat, and anthropometric estimates of limb muscle volumes. Small to trivial improvements of experimental subjects relative to control subjects included peak power (p < 0.001), 1RM strength measures (p < 0.01), sprint times (p < 0.001 for 5 m; p < 0.05 for 30 m), COD (p < 0.01), and all RCOD parameters (p < 0.05) except the RCOD fatigue index. However, vertical jump parameters and limb volumes remained unchanged relative to controls. It may be concluded that adding biweekly elastic band training to a standard conditioning regimen yields small gains in measures that likely have an important influence on handball performance, particularly the ability to sprint, change direction, and make repeated changes of direction. Accordingly, such simple exercises can usefully be adopted as a component of handball training.

Foundational insights into the estimation of whole-body metabolic rate.

Since 2013, this journal has promoted the publication of thematic reviews (Taylor in Eur J Appl Physiol 113:1634, 2013), where leading groups were invited to review the critical literature within each of several sub-topics. The current theme is historically based, and is focussed on estimating the metabolic rate in humans. This review charts the development of our understanding of those methods, from the discovery of oxygen and carbon dioxide, to the introduction of highly sophisticated modern apparatus to examine the composition of expired gas and determine respiratory minute volume. An historical timeline links the six thematic vignettes on this theme. Modern advances have greatly enhanced data collection without significant decrements in measurement accuracy. At the same time, however, conceptual errors, particularly steady-state requirements, are too often ignored. Indeed, it is recognised that we often neglect the past, leading to errors in research design, experimental observations and data interpretation, and this appears to be increasingly prevalent within the open-access literature. Accordingly, the Editorial Board, in recognition of a widening gap between our experimental foundations and contemporary research, embarked on developing a number of thematic review series, of which this series is the first. The intent of each accompanying overview is to introduce and illuminate seminal investigations that led to significant scientific or intellectual breakthroughs, and to thereby whet the appetite of readers to delve more deeply into the historical literature; for it is only when the foundations are understood that we can best understand where we are now, and in which directions we should head.

Effects of Lower-Limb Strength Training on Agility, Repeated Sprinting With Changes of Direction, Leg Peak Power, and Neuromuscular Adaptations of Soccer Players.

Hammami, M, Negra, Y, Billaut, F, Hermassi, S, Shephard, RJ, and Chelly, MS. Effects of lower-limb strength training on agility, repeated sprinting with changes of direction, leg peak power, and neuromuscular adaptations of soccer players. J Strength Cond Res 32(1): 37-47, 2018-We examined the effects on explosive muscular performance of incorporating 8 weeks strength training into the preparation of junior male soccer players, allocating subjects between an experimental group (E, n = 19) and a matched control group (C, n = 12). Controls maintained their regular training program, but the experimental group replaced a part of this schedule by strength training. Performance was assessed using running times (5, 10, 20, 30 and 40 m), a sprint test with 180° turns (S180°), a 9-3-6-3-9 m sprint with backward and forward running (SBF), a 4 × 5 m sprint test with turns, repeated shuttle sprinting, repeated changes of direction, squat (SJ) and counter-movement (CMJ) jumping, back half-squatting, and a force-velocity test. Electromyographic (EMG) activity of the vastus lateralis (VL), vastus medialis (VM), and rectus femoris (RF) muscles was recorded during jumping. Two-way ANOVA showed significant gains in E relative to C during the straight sprint (all distances). Scores of E increased substantially (p ≤ 0.01) on S4 × 5 and SBF and moderately on S180°. Leg peak power, SJ, and CMJ were also enhanced, with significant increases in EMG activity. However, repeated-sprint parameters showed no significant changes. We conclude that biweekly strength training improves key components of performance in junior soccer players relative to standard in-season training.

Open-circuit respirometry: a brief historical review of the use of Douglas bags and chemical analyzers.

The Douglas bag technique is reviewed as one in a series of articles looking at historical insights into measurement of whole body metabolic rate. Consideration of all articles looking at Douglas bag technique and chemical gas analysis has here focused on the growing appreciation of errors in measuring expired volumes and gas composition, and subjective reactions to airflow resistance and dead space. Multiple small sources of error have been identified and appropriate remedies proposed over a century of use of the methodology. Changes in the bag lining have limited gas diffusion, laboratories conducting gas analyses have undergone validation, and WHO guidelines on airflow resistance have minimized reactive effects. One remaining difficulty is a contamination of expirate by dead space air, minimized by keeping the dead space <70 mL. Care must also be taken to ensure a steady state, and formal validation of the Douglas bag method still needs to be carried out. We may conclude that the Douglas bag method has helped to define key concepts in exercise physiology. Although now superceded in many applications, the errors in a meticulously completed measurement are sufficiently low to warrant retention of the Douglas bag as the gold standard when evaluating newer open-circuit methodology.

Exercise and the Athlete With Infectious Mononucleosis.

OBJECTIVE: To determine appropriate management of the active individual with infectious mononucleosis (IM), including issues of diagnosis, the determination of splenomegaly, and other measures of disease status, the relationship of the disease to chronic fatigue syndrome (CFS), and the risks of exercise at various points in the disease process. DATA SOURCES: An Ovid/MEDLINE search (January 1996-June 2015) was widely supplemented by "similar articles" found in Ovid/MEDLINE and PubMed, reference lists, and personal files. MAIN RESULTS: Clinical diagnoses of IM are unreliable. Traditional laboratory indicators (lymphocytosis, abnormal lymphocytes, and a heterophile-positive slide test) can be supplemented by more sensitive and more specific but also more costly Epstein-Barr antigen determinations. Clinical estimates of splenomegaly are fallible. Laboratory determinations, commonly by 2D ultrasonography, must take account of methodology, the formulae used in calculations and the individual's body size. The SD of normal values matches the typical increase of size in IM, but repeat measurements can help to monitor regression of the disease. The main risks to the athlete are spontaneous splenic rupture (seen in 0.1%-0.5% of patients and signaled by acute abdominal pain) and progression to chronic fatigue, best avoided by 3 to 4 weeks of restricted activity followed by graded reconditioning. A full recovery of athletic performance is usual with 2 to 3 months of conservative management. CONCLUSIONS: Infectious mononucleosis is a common issue for young athletes. But given accurate diagnosis and the avoidance of splenic rupture and progression to CFS through a few weeks of restricted activity, long-term risks to the health of athletes are few.

Cancers of the Esophagus and Stomach: Potential Mechanisms Behind the Beneficial Influence of Physical Activity.

OBJECTIVE: To compare findings from several recent meta-analyses showing a reduced risk of gastric and esophageal cancers in physically active individuals, to assess the magnitude of this benefit, and to seek information on potential underlying mechanisms. DATA SOURCES: A comprehensive search of Ovid/Medline from 1996 to February 2016, using the terms physical activity or exercise or training and esophageal or gastric cancer, and supplementing the articles identified by material from references lists and personal files. MAIN RESULTS: Moderate-to-vigorous physical activity is associated with a 20% to 30% reduction in the risk of gastroesophageal adenocarcinomas, with a significant dose/response relationship. Benefit is greater in women than in men, and greater for noncardia than for cardia or esophageal tumors. Mechanisms could include a reduction of visceral fat (with a lesser production of cancer promoting hormones and reduced gastroesophageal reflux) and/or a lesser likelihood of smoking and excessive alcohol consumption. Physical activity does not protect against Helicobacter pylori infections or gastric ulceration, but mechanisms related to the impact of exercise on immune function, antioxidant mechanisms, and gastroesophageal reflux remain to be explored. CONCLUSIONS: Regular, moderate-to-vigorous physical activity is associated with a clinically significant reduction in the risk of gastroesophageal adenocarcinomas, but mechanisms are as yet unclear, and a causal relationship remains to be proven.

The Effect of Standard Strength vs. Contrast Strength Training on the Development of Sprint, Agility, Repeated Change of Direction, and Jump in Junior Male Soccer Players.

Hammami, M, Negra, Y, Shephard, RJ, and Chelly, MS. The effect of standard strength vs. contrast strength training on the development of sprint, agility, repeated change of direction, and jump in junior male soccer players. J Strength Cond Res 31(4): 901-912, 2017-The aim was to compare the impact of 2 differing strength training (ST) programs on the athletic performance of junior male soccer players at a critical phase during their competitive season. Participants aged 16.0 ± 0.5 years were randomly assigned between control (C, n = 12), standard ST (n = 16), and contrast strength training (CST, n = 16), each performed twice a week. Athletic performance was assessed before and after the intervention using 8 tests: 40-m sprint, 4 × 5-m sprint (S4 × 5), 9-3-6-3-9 m sprint with 180° turns (S180°), 9-3-6-3-9 m sprint with backward and forward running (SBF), repeated shuttle sprint ability (RSSA), repeated change of direction (RCOD), squat jump (SJ), and countermovement jump (CMJ). The control group's (CG) performance tended to improve in some tests and decrease in others, but these changes were not statistically significant. Both training programs enhanced all sprint performances relative to controls (p ≤ 0.05). The strength training group (SG) and the CST group (CSG) increased significantly in S180°, SBF, and S4 × 5 relative to CG, although the S4 × 5 also increased in CSG relative to SG (p ≤ 0.05). No intergroup difference of RSSA performance was observed. The RCOD parameters increased significantly in CSG relative to both SG and CG (p ≤ 0.05). The SJ and CMJ height increased significantly in both experimental groups (p < 0.000). We conclude that during the competitive season, some measures of athletic performance in male soccer players were increased more by 8 weeks of CST than by ST.

Responses of the human spleen to exercise.

The human spleen shows a decrease in volume of around 40% early during vigorous exercise and in response to other stressful stimuli such as maximal apnoea and the breathing of hypoxic gas mixtures. Contraction seems an active response, mediated by alpha-adrenergic fibres in the splenic nerve. Given the relatively small size of the human spleen, the effect upon physical performance is likely to be small; the augmentation of total blood volume is <2%, and even taking account of other causes of haemoconcentration during vigorous exercise, the increase of haematocrit is <10%. However, one of two studies suggested that the haemoconcentration may be sufficient to cause errors in the traditional method for calculating exercise-induced changes of plasma volume. The spleen also contributes leucocytes and platelets to the general circulation as part of the "fight or flight" reaction to stressors. The mobilisation of leucocytes proceeds more slowly than that of the red cells; it depends not only upon an active contraction of the spleen, but also a modulation of leucocyte adhesion molecules. Splenectomy impairs exercise performance in horses, but human performance data are lacking; overall health effects seem minimal, and many patients live many years after removal of their spleens.

Effects of an In-season Plyometric Training Program on Repeated Change of Direction and Sprint Performance in the Junior Soccer Player.

Hammami, M, Negra, Y, Aouadi, R, Shephard, RJ, and Chelly, MS. Effects of an in-season plyometric training program on repeated change of direction and sprint performance in the junior soccer player. J Strength Cond Res 30(12): 3312-3320, 2016-We aimed to determine the gains in explosive movements of male junior soccer players induced by incorporating an 8-week plyometric training program (PTP) into a standard soccer conditioning regimen 5 months after the beginning of the competitive season. Our hypothesis was that PTP would enhance explosive movements, and thus sprint running, repeated shuttle sprint ability (RSSA), agility and the ability to make repeated changes of direction (RCOD). A group of junior soccer players were randomly divided into 2 groups: an experimental group (E, n = 15, age 15.7 ± 0.2 years) and a control group (C, n = 13, age 15.8 ± 0.2 years). The participants in E and C performed training exercises and matches together, but for an 8-week period in the latter part of the season, the experimental group replaced a part of the normal regimen (the tactical session) by a biweekly course of PTP (hurdle and drop jumps). Two familiarization sessions were held 2 weeks before definitive testing. The ability of the players was assessed by 3 agility tests (a sprint test with 180° turns, a 9-3-6-3-9 m sprint with backward and forward running, and a four 5-m sprint test with turns); 2 repeated sprint tests (RSSA and RCOD); and running times over 5-, 10-, 20-, 30-, and 40-m distances. Participants in E showed gains relative to C in sprint times (p ≤ 0.05 for 5, 10, and 20 m), and 2 of 3 the RCOD parameters (RCOD best, p ≤ 0.001; RCOD total, p ≤ 0.05). However, with the pattern of plyometric training that we adopted, and perhaps because participants were in good initial physical condition, the agility and RSSA test scores remained unchanged. Nevertheless, we conclude that our PTP can be commended to junior soccer players as a means of improving important components of their physical performance.

Effects of physical activity upon the liver.

PURPOSE: To review the responses of the liver to acute and chronic physical activity and to summarize relationships between physical activity and liver health. METHODS: A systematic search of HealthStar/Ovid from 1975 through June of 2013, supplemented by articles from other sources. RESULTS: 351 of 8,010 articles identified by HealthStar/Ovid were supplemented by 92 other papers; after focussing, the review was reduced to 435 citations. Prolonged acute exercise reduces hepatic blood flow, stimulating hepatic glycogenolysis, gluconeogenesis and synthesis of some proteins; however, lipid metabolism shows little change. Glutathione depletion suggests oxidative stress. Enzymes affecting carbohydrate metabolism are up-regulated, and lipogenic enzymes are down-regulated. The main triggers are humoral, but hepatic afferent nerves, cytokines, reactive oxygen species, and changes in hepatic blood flow may all play some role. Regular aerobic exercise training improves blood glucose control during exercise by increasing glycogen stores and up-regulating enzymes involved in gluconeogenesis and carbohydrate metabolism. Resistance to oxidant stress is generally increased by training. Lipogenic enzymes are down-regulated, and lipid metabolism is augmented. Modulations of insulin, insulin-like growth factor, glucagon and interleukin-6 may trigger the adaptive responses to training. Cross-sectional and longitudinal studies show that regular exercise can reduce hepatic fat, but the effect on circulating aminotransferases is unclear and the modality and dose of physical activity optimizing health benefits need clarification. CONCLUSIONS: Regular moderate physical activity enhances liver health. Adverse functional changes can develop if habitual activity is inadequate, and extremely prolonged competitive exercise may also be harmful, particularly under harsh environmental conditions.