A Systematic Review of the Effects of Caffeine on Basketball Performance Outcomes

Caffeine is an ergogenic aid in many sports, including basketball. This systematic review examines the effects of caffeine on basketball-related skill tasks along with physical aspects of performance deemed important for the game. A systematic search was conducted across three databases (PubMed, SPORTDiscus and Web of Science) to identify randomized-controlled trials which examined the effect of caffeine on basketball performance outcomes including: free-throw, 3-point shooting accuracy, dribbling speed, vertical jump height, and linear and repeated sprints. Forty-six articles were identified of which 10 met the inclusion criteria. Improvements in vertical jump were identified in four of five studies, agility in two of four studies, and in linear and repeated sprints in two of three studies. No deterioration in basketball skills performance was observed in any studies. It is suggested that caffeine is useful for basketball players to improve the physical aspects of their game-play performance but there is little evidence of any change in skill-based performance at present. Further research should clarify the effects of caffeine on basketball performance in women and the role of individual genetic variation on caffeine metabolism. Basketball players and coaches should be aware of the properties of caffeine before ingesting it as an ergogenic supplement.

Can IMU Provide an Accurate Vertical Jump Height Estimate?

The aim of the present study was to determine if an inertial measurement unit placed on the metatarsal part of the foot can provide valid and reliable data for an accurate estimate of vertical jump height. Thirteen female volleyball players participated in the study. All players were members of the Republic of Serbia national team. Measurement of the vertical jump height was performed for the two exemplary jumping tasks, squat jump and counter-movement jump. Vertical jump height estimation was performed using the flight time method for both devices. The presented results support a high level of concurrent validity of an inertial measurement unit in relation to a force plate for estimating vertical jump height (CMJ t = 0.897, p = 379; ICC = 0.975; SQJ t = −0.564, p = 0.578; ICC = 0.921) as well as a high level of reliability (ICC > 0.872) for inertial measurement unit results. The proposed inertial measurement unit positioning may provide an accurate vertical jump height estimate for in-field measurement of jump height as an alternative to other devices. The principal advantages include the small size of the sensor unit and possible simultaneous monitoring of multiple athletes.

Fitness Fights Fires: Exploring the Relationship between Physical Fitness and Firefighter Ability

Background: Regular exercise in firefighters may be effective in preventing or attenuating ill health (e.g., hypertension, diabetes, and obesity), as well as improving their firefighting ability. The purpose of this study was to investigate the relationship between physical fitness and firefighting ability. Methods: Male firefighter recruits’ (n = 89; age = 27.1 ± 4.2 yrs) physical fitness and firefighting ability were assessed at Week 1 and Week 7 during a basic firefighting training academy. Physical fitness was assessed via 1.5 mile run time, sit-up and push-up repetitions, the Young Men’s Christian Association (YMCA) bench press test, vertical jump height, and sit-and-reach flexibility, while firefighting ability was assessed via completion time on a firefighting skills test. Results: Fitness predicted significant variance in firefighting ability at Week 1 (R2= 0.46; p < 0.01) and Week 7 (R2 = 0.46; p < 0.01), after accounting for age and body mass index. Cardiovascular endurance accounted for 22.4% (FΔ (1, 85) = 25.75) and 39.3% (FΔ (1, 85) = 55.53) while muscular endurance accounted for an additional 19.0% (FΔ (3, 82) = 10.34) and 6.3% (FΔ (3, 82) = 3.2) unique variance in firefighting ability at Week 1 and Week 7, respectively. Conclusions: Given the strong association between fitness and firefighting performance, municipal departments may want to focus on increasing fitness levels among firefighters.

The Effects of Successive Soccer Matches on the Internal Match Load, Stress Tolerance, Salivary Cortisol and Jumping Performance in Youth Soccer Players

The study aim was to analyze the effects of successive matches on the internal match load, stress tolerance, salivary cortisol concentration and countermovement vertical jump height in twelve youth soccer players (16.6 ± 0.5 yr; 175 ± 8 cm; 65 ± 8 kg) who performed four official matches within a four day-period with a 24-h recovery interval between the matches. The internal match load, monotony index and competitive strain, as well as stress tolerance were examined. Saliva samples were collected and countermovement vertical jump height was assessed 60 min pre and 30 min post each match; delta of salivary cortisol and countermovement vertical jump height for each match were analyzed. Salivary cortisol was analyzed using an enzyme-linked immunosorbent assay. The results of ANOVA with repeated measures showed no differences between matches for the internal match load (p > 0.05). The scores of the monotony index and competitive strain were 4.3 (±2.3) and 8104 (±6795) arbitrary units, respectively. There was no difference for stress tolerance between matches (p > 0.05). Delta values of salivary cortisol were not different among the assessed matches (F(3,33) = 1.397, p = 0.351, η2: 0.09); however, delta of countermovement vertical jump height decreased from match 1 to match 4 (F(3,33) = 8.64, p < 0.001, η2: 0.44). The current findings suggest that participating in four successive matches, with 24-h of recovery in between, may not lead to changes in stress tolerance and salivary cortisol of youth players, but it may induce a decrease in players’ jumping performance after the fourth match.

Ankle Orthosis-induced Decrease in Repetitive Rebound Jump Height: Relationship With Restriction in Sagittal Ankle Range of Motion

Background: Ankle orthotics decreases the maximal vertical jump height. It is essential to maximize jump height and minimize ground contact time during athletic performance. However, the effect of ankle orthotics on athletic performance has not been reported. We aimed to investigate the effect of ankle orthotics on squat jump (SJ), countermovement jump (CMJ), and repetitive rebound jump (RJ) performance and the relationship between jump performance and restriction in sagittal ankle range of motion. Methods: Twenty healthy volunteers performed SJ, CMJ, repetitive RJ under no-orthosis and two orthotic conditions (orthosis 1 and orthosis 2). During SJ and CMJ, we measured the vertical ground reaction force and calculated the following parameters: jump height, peak vertical ground reaction force, rate of force development, net vertical impulse, and peak power. During repetitive RJ, the jump height, contact time, and RJ index were measured. A two-dimensional motion analysis was used to quantify the ankle range of motion in the sagittal plane during SJ, CMJ, and repetitive RJ. Results: Multivariate analysis of variance and the post hoc test showed a significant decrease in the vertical jump height (p = 0.003), peak power (p = 0.007), and maximum plantarflexion and dorsiflexion angles (p <0.001) during SJ using orthosis 2 compared to those using the no-orthosis condition. Additionally, orthosis 2 significantly decreased the jump height at the end of repetitive RJ (p = 0.046), during which a significant negative correlation was found between jump height and maximum dorsiflexion angle (r = 0.485, p = 0.030). Conclusions: An ankle orthosis-induced restriction of dorsiflexion is associated with a reduction in jump height during static jump and repetitive RJ performance.

Class Year Differences in Anthropometric and Fitness Measures in Division I Field Hockey Athletes Pre and Post Season

The purpose of this study was to investigate the way in which anthropometric and fitness measures vary by class year before and after a Division I female field hockey competitive season. Anthropometric (mass and percent body fat) and fitness measures (vertical jump and Yo-Yo Intermittent Recovery Test 1 (Yo-Yo IR1) distance) were collected on 16 athletes (mean ± SD: age = 19.5 ± 0.9 years) before and after a competitive season. Class year, based on the athlete’s year in college, was used to group athletes in the study. Body mass, vertical jump height, and Yo-Yo IR1 distance all increased pre to post season (p < 0.05). First-year athletes had a significantly lower body mass, vertical jump height and Yo-Yo IR1 distance compared to other class years across the testing period (p < 0.05). Post season levels for first-years were lower than both pre and post season levels for sophomore or junior athletes. Team mean vertical jump increased 8.9%, with all but two athletes improving. Team mean Yo-Yo IR1 distance increased 16.4%. Athlete training over the course of the study was designed to improve on field playing performance and training was not directly select to improve measures in the study; therefore, the potential success of integrating fitness, speed, and strength development into technical training sessions is indicated. Coaches should be aware that first-year athletes may not be at the same level of conditioning as sophomores and juniors. Coaches should work specifically with the first-year athletes during the season to monitor their fitness levels.

PROFESSIONAL MARTIAL ARTISTS’ KINEMATIC AND KINETIC CHANGES IN VERTICAL JUMP PERFORMANCE AND BODY COMPOSITION BEFORE AND AFTER COVID-19 LOCKDOWN

The COVID-19 pandemic has caused mandatory lockdowns leading to disruptions in sports training programs. This study aimed to determine the effects of a 16-week COVID-19 lockdown on body composition as well as kinetic and kinematic parameters of the countermovement jump (CMJ) for professional martial artists. Thirteen (n=13) professional martial artists participated in this retrospective cohort study. Subjects were tested on the CMJ at four timepoints: 1) pre-lockdown (pre), 2) immediately post-lockdown (post), 3) two weeks post-lockdown (post+2), and 4) four weeks post-lockdown (post+4). Body composition was measured via bioelectrical impedance and jump data were collected using a force platform sampling at 1,000 Hz. Individual repeated-measures ANOVAs were conducted with pairwise post-hoc analyzes. Differences were observed in vertical jump height (VJH) of 10.33%, peak velocity (PV) of 3.10%, reactive strength index modified (RSImod) of 13.8%, and peak propulsive power (PPP) of 6.00% (p&lt;0.05). There as an increase from post to post+2 of 13.06% in VJ, 4.12% for PV, 14.0% for RSImod, and PPP of 4.66%. There was an increase from post to post+2 of 10.8% in VJH, 3.1% for PV, 14.0% for RSImod, and PPP of 3.0%. Fat mass (FM) and BF% increased from pre to post by 13% and 11%, respectively, and decreased 8% and 11% from post to post+4 respectively (p&lt;0.05). In contrast, there was an decrease in fat-free mass (FFM) from pre to post of 11% and a decrease of 8% from post to post+4. There were moderate associations between FFM and VJH (rmc=0.47), FMM and PPP (rmc=0.47), FFM and PV (rmc=0.47), BF% and PV (rmc=-0.42), and FM and PV (rmc=0.42). While the lockdown resulted in a significant decrease in CMJ performance and increases in BF and FM, subjects’ performance returned to pre-lockdown levels after only 2-4 weeks of post-lockdown training by decreasing BF, FM, and increasing FFM.

Physical and performance characteristics related to starter status, position, and division in Japanese collegiate American-football players

BACKGROUND: Few studies have investigated the variations in body composition and performance in Japanese collegiate American-football players. OBJECTIVE: To clarify what characterizes competitors at the highest levels – in the top division or on the starting lineup – we compared players’ body compositions and performance test results. METHODS: This study included 172 players. Each player’s body composition and performance (one-repetition maximum bench press, one-repetition maximum back squat, and vertical jump height) were measured; power was estimated from vertical jump height and body weight. Players were compared according to status (starter vs. non-starter), position (skill vs. linemen), and division (1 vs. 2). Regression analysis was performed to determine characteristics for being a starter. RESULTS: Players in higher divisions and who were starters were stronger and had more power, greater body size, and better performance test results. Players in skill positions were relatively stronger than those in linemen positions. Vertical jump height was a significant predictor of being a starter in Division 1. CONCLUSION: Power and vertical jump may be a deciding factor for playing as a starter or in a higher division.