Physical and performance characteristics of Japanese division 1 collegiate football players

Iguchi, J, Yamada, Y, Ando, S, Fujisawa, Y, Hojo, T, Nishimura, K, Kuzuhara, K, Yuasa, Y, and Ichihashi, N. Physical and performance characteristics of Japanese division 1 collegiate football players. J Strength Cond Res 25(12): 3368-3377, 2011-This study aimed to establish the physical and performance characteristics of football players in the Japanese Division 1 collegiate football program and perform a comparison of these characteristics between Japanese (n = 208) and US Division 1 football players (n = 797). The following comparisons were made: (a) between a higher-ranked university team vs. a lower-ranked university team in Japan, (b) between different playing positions in Japan, (c) between starters and nonstarters in Japan, and (d) between playing positions in Japan vs. those in the United States. The results of this study suggest that players in the higher-ranked university team were heavier, stronger in back squat, jumped higher, and had greater power than those on the lower-ranked team. Furthermore, linemen were generally characterized by larger size, greater strength, and more fat as compared with backs. On the other hand, backs tended to be faster, smaller in physical size, have higher vertical jump height, and show greater relative strength than linemen did. Starters were taller, heavier, stronger, had more powerful, and more fat-free mass than nonstarters. Finally, our results revealed that players in the United States were superior to players in Japan in all body status comparisons (p < 0.01). This study revealed that performance and superior body composition are essential for the success of a football player. Power and strength seem to be key factors in defining good football performance.     

Equipment and running surface alter sprint performance of college football players

The purpose of this study was to determine the effect of football equipment and running surface on sprint performance in NCAA Division II football players (n = 68). Players were timed in the 40-yd sprint on an indoor rubberized track (Day 1) and on an outdoor, natural-grass football field (Day 2) wearing either regulation football equipment or shorts and a T-shirt. Each player was assigned randomly to perform 2 trials under each condition on each surface, and the average of the 2 trials was used for analysis. Offensive backs, defensive backs, and linebackers were significantly faster than were offensive and defensive linemen in all trials, and subjects were collapsed into 2 groups, backs and linemen. Football equipment significantly impaired performance on the track (-2.8% +/- 1.7%) and the field (-2.9% +/- 1.8%). The increase in body mass due to the football equipment was significantly greater for backs (7.2% +/- 0.7%) than for linemen (6.5% +/- 1.0%), but produced a significantly greater impairment in sprint performance in linemen (-3.3% +/- 1.1%) as compared with backs (-2.5% +/- 1.5%). Sprint performance was significantly and equivalently impaired when running on grass (backs: -2.5 +/- 1.1%; linemen: -2.8 +/- 1.4%) as compared with the track. Thus, running a 40-yd sprint in football equipment on a natural grass field impairs performance by an average of 5.5% (+/- 2.3%) compared with running indoors with minimal apparel. Football equipment and running surface significantly impair sprint performance in college football players, the effect being greater in linemen than in backs, and is likely related to differences in muscle strength/power and body fat.     

Comparison of selected physical fitness and performance variables between NCAA Division I and II football players

The purpose of this study was to compare selected physical fitness and performance variables between National Collegiate Athletic Association (NCAA) Division I and II football players. The subjects included offensive and defensive starters, excluding kickers and punters from 26 NCAA Division I and 23 Division II teams. Offensive players were grouped and compared by the following positions: quarterback, running back, wide receiver, tight end, and line. Defensive players were grouped and compared by the following positions: line, linebackers, and backs. Division I players were better in 58 of 117 comparisons (p < or = 0.01). Division II players were not found to be better in any of the variables studied.     

The effects of training history, player position, and body composition on exercise performance in collegiate football players

Performance data for 261 NCAA Division 1A collegiate football players were analyzed to determine if player position, body weight, body fat, and training time were correlated with changes in performance in the following events: power clean (PC), bench press (BP), squat (SQ), vertical jump (VJ), 40-yd dash (40yd), and 20-yd shuttle (20yd). Individual positions were combined into the following groups: (A) wide receivers, defensive backs, and running backs, (B) linebackers, kickers, tight ends, quarterbacks, and specialists, and (C) linemen. Increases in body weight were positively correlated with increases in BP and PC performance for all groups. Increases in body fat were negatively correlated with performance in the PC and VJ for all groups. For group C, increases in body fat were also negatively correlated with performance in the 40yd and 20yd. Group and training time exhibited no linear relationship with performance in any of the tested events. No linear relationships were observed between the independent variables and performance in the SQ. When individual training data were analyzed longitudinally, a nonlinear increase in performance in the PC, BP, and SQ was observed as training time increased, with the greatest rate of change occurring between the first and second semesters of training.     

The National Football League combine: a reliable predictor of draft status?

The performance of 326 collegiate football players attending the 2000 National Football League combine was studied to determine whether draft status could be predicted from performance measurements. The combine measured height and weight along with 9 performance tests: 225-lb bench press test, 10-yd dash, 20-yd dash, 40-yd dash, 20-yd proagility shuttle, 60-yd shuttle, 3-cone drill, broad jump, and vertical jump. Prediction equations were generated for 7 position categories with varying degrees of accuracy-running backs (RBs), r(2) = 1.00; wide receivers (WRs), r(2) = 1.00; offensive linemen, r(2) = 0.70; defensive linemen, r(2) = 0.59; defensive backs (DBs), r(2) = 1.00; linebackers, r(2) = 0.22; and quarterbacks, r(2) = 0.84. The successes of the prediction equations are related to the ability of the individual tests to assess the necessary skills for each position. This study concludes that the combine can be used to accurately predict draft status of RBs, WRs, and DBs. The equations can also be used as a good to fair estimate for other positions.     

Body composition in Division I football players

This study assessed body composition of Division I football players (n = 69) and compared the findings with previously reported data to ascertain whether the increase in player total body mass that has been observed over the past 10 years has been accompanied by an increase in body fat. Body composition was determined by hydrostatic weighing and the measurement of skinfold thicknesses. Total body mass, skinfold thicknesses, and body fat were greater in the current players than in players in studies conducted in the early 1980s and early 1990s. Body fat varied significantly across playing position, with the defensive backs, offensive backs, and receivers being the leanest and the offensive linemen and tight ends the most fat. There was no significant relationship between body composition and playing year or scholarship status, nor were any differences observed between ethnic groups. Of important clinical relevance was the finding that the linemen (offensive, defensive) and tight ends were on average greater than 25% body fat, the borderline for obesity in this age group. Much of this fat was deposited in the abdominal region, a significant finding when one considers the high correlation between abdominal obesity and ischemic heart disease and stroke. The current findings suggest that more attention needs to be given to the nature of the increase in body mass being achieved by today's football player to minimize long-term negative health consequences, and the findings reemphasize the need identified in earlier studies of the importance of detraining programs for these athletes.     

Comparison of the backward overhead medicine ball throw to power production in college football players

The purpose of this study was to determine the relationship of the backward overhead medicine ball (BOMB) throw to power production in college football players. Forty National Collegiate Athletic Association Division II college football players were studied at the end of an 8-week off-season conditioning program for power output determined from a countermovement vertical jump on a force plate and for maximal distance in the standing BOMB throw. Although the reliability of the BOMB test was high (interclass correlation coefficient = 0.86), there was a significant learning effect across 3 trials (p < 0.01). Peak and average powers generated during the vertical jump correlated moderately but significantly with the best BOMB throw distance (r = 0.59 and 0.63, respectively). Considering power relative to body mass or lean body mass failed to produce significant correlations with BOMB throw distance (r = 0.27 and 0.28, respectively). Therefore, the BOMB throw may have limited potential as a predictor of total body explosive power in college football players.     

Body composition relates poorly to performance tests in NCAA Division III football players

We assessed body composition (height, body mass, body mass index, body fat by densitometry, fat mass, fat-free mass, and lean/fat ratio) and performance (10- and 40-yd sprints, pro shuttle run, vertical jump, sit and reach, and bench press) in 77 National Collegiate Athletic Association Division III football players. Data were analyzed by position and playing status. Significant differences (p 相似文献   

Strength and power characteristics in English elite rugby league players

The aim of this article is to present data on the strength and power characteristics of forwards and backs in a squad of elite English rugby league players and compare these findings to previously published literature from Australia. Participants were elite English rugby league players (n = 18; height 184.16 ± 5.76 cm; body mass 96.87 ± 10.92 kg, age 21.67 ± 4.10 years) who were all regular first team players for an English Superleague club. Testing included 5-, 10-, 20-m sprint times, agility, vertical jump, 40-kg squat jump, isometric squat, concentric and eccentric isokinetic knee flexion and extension. Independent t-tests were performed to compare results between forwards and backs, with paired samples t-tests used to compare bilateral differences from isokinetic assessments and agility tests. Forwards demonstrated significantly (p < 0.05) greater body mass (102.15 ± 7.5 kg), height (186.30 ± 5.47 cm), power during the 40-kg jump squat (2,106 ± 421 W), isometric force (3,122 ± 611 N) and peak torque during left concentric isokinetic knee extension (296.1 ± 54.2 N·m) compared to the backs (86.30 ± 8.97 kg; 179.87 ± 3.72 cm; 1,709 ± 286 W; 2,927 ± 607 N; 241.7 ± 35.2 N·m, respectively). However, no significant differences (p > 0.05) were noted between forwards and backs during right concentric isokinetic knee extension (274.8 ± 37.7 and 246.8 ± 25.8 N·m), concentric isokinetic knee flexion for both left (158.8 ± 28.6 and 141.0 ± 22. 7 N·m) and right legs (155.3 ± 22.9 and 128.0 ± 23.9 N·m), eccentric isokinetic knee flexion and extension, hamstring quadriceps ratios, or vertical jump (37.25 ± 4.35 and 40.33 ± 6.38 cm). In comparison, relative measures demonstrated that backs performed significantly better compared to the forwards during the 40-kg jump squat (20.71 ± 5.15 and 19.91 ± 3.91 W·kg?1) and the isometric squat (34.32 ± 7.9 and 30.65 ± 5.34 N·kg?1). Bilateral comparisons revealed no significant differences (p > 0.05) between left and right leg performances in the agility test (3.26 ± 0.18 and 3.24 ± 0.18 seconds), or between left (0.7 ± 0.10) and right (0.71 ± 0.17) leg eccentric hamstring concentric quadriceps ratios. The results demonstrate that absolute strength and power measures are generally higher in forwards compared to in backs; however, when body mass is taken into account and relative measures compared, the backs outperform the forwards.     

Countermovement vertical jump with drop step is higher than without in collegiate football players

The vertical jump is a performance test commonly used to assess explosive power and predict athletic ability. Typically, the vertical jump is performed with a countermovement from a stationary stance. We hypothesized that taking a quick step back before initiating the jump, known as the drop-step technique, would result in a higher vertical jump. The purpose of this study was to compare countermovement vertical jumps (CMJs) done from the stationary-stance position to CMJs performed with the drop-step with trained athletes. NCAA Division I football players (N = 56) performed 3 trials each of stationary-stance and drop-step CMJs in a random order. A paired t test revealed that a significantly (p < 0.01) higher jump height was achieved with the drop-step CMJ (69.3 +/- 8.0 cm) compared to the stationary-stance CMJ (66.5 +/- 8.0 cm). The 2 jump conditions were highly related (r = 0.95), and the rank order of the athletes tended to be similar from 1 condition to the other (rho = 0.94). Trial-to-trial reliability was similar for each condition (coefficient of variation [CV] = 3.5% stationary stance; CV = 4.1% drop step). It is important to standardize CMJ testing procedures because a significant difference in the height achieved exists between the stationary-stance and drop-step techniques.     

Relationship between football playing ability and selected performance measures

The relationships between football playing ability (FPA) and selected anthropometric and performance measures were determined among NCAA Division I-A football players (N = 40). Football playing ability (determined by the average of coaches' rankings) was significantly correlated with vertical jump (VJ) in all groups (offense, defense, and position groups of wide receiver-defensive back, offensive linemen-defensive linemen, and running back-tight end-linebacker). Eleven of 50 correlations (groups by variables), or 22%, were important for FPA. Five of the 11 relationships were related to VJ. Forward stepwise regression equations for each group explained over half of the criterion variable, FPA, as indicated by the R(2) values for each model. Vertical jump was the prime predictor variable in the equations for all groups. The findings of this study are discussed in relation to the specificity hypothesis. Strength and conditioning programs that facilitate the capacity for football players to develop forceful and rapid concentric action through plantar flexion of the ankle, as well as extension of the knee and hip, may be highly profitable.     

Nonfunctional overreaching during off-season training for skill position players in collegiate American football

The purpose of this study was to determine the performance and hormonal responses to a 15-week off-season training program for American football. Nine skill position players from a National Collegiate Athletic Association (NCAA) Division I-A football team participated as subjects in this study. Following 4 weeks of weight training (phase I), subjects performed weight training concurrently with high-volume conditioning drills (phase II). Phase III consisted of 15 spring football practice sessions executed over a 30-day period. Performance and hormonal changes were assessed prior to phase I, and following phases I, II, and III. Maximal strength was significantly increased (p < 0.05) for all strength tests during phase I. Squat and power clean values decreased following phase II (p < 0.05), with all values returning to baseline upon completion of phase III. Sprinting speed significantly worsened during phase I (p < 0.05), but then returned to baseline during phase III. Vertical jump and agility improved during phase I (p < 0.05), with vertical jump remaining unchanged for the duration of the study and agility returning to baseline following phase II. Testosterone levels decreased during phase II (p < 0.05) prior to returning to baseline levels during phase III. Cortisol and the testosterone/cortisol ratio remained unchanged during the course of the investigation. Even though overtraining did not occur in the current investigation, a significant maladaptation in performance did occur subsequent to phase II. For this particular athletic population, a strength and conditioning program utilizing a reduced training volume-load may prove more effective for improving performance in the future.     

Body size and composition of National Football League players

The purpose of this study was to present a profile of body size and composition of National Football League (NFL) players prior to the start of the regular season. Fifty-three members of the Indianapolis Colts professional football team were measured for height, body mass, and percentage body fat using the BOD POD air-displacement plethysmography system during summer camp of the 2003 football season. These data were categorized by position for comparison with previous studies of NFL football players. The relationships observed were as follows (= represents nonsignificant; > represents p < or = 0.05): Height: Offensive Line = Defensive Line = Quarterbacks/Kickers/Punters = Tight Ends > Linebackers > Running Backs = Wide Receivers = Defensive Backs. Body Mass: Offensive Line = Defensive Line > Tight Ends = Linebackers > Running Backs = Quarterbacks/ Kickers/Punters > Wide Receivers = Defensive Backs. Percentage Body Fat: Offensive Line > Defensive Line > Quarterbacks/ Kickers/Punters = Linebackers = Tight Ends > Running Backs = Wide Receivers = Defensive Backs. Comparisons to teams in the 1970s indicate that body mass has increased only for offensive and defensive linemen; however, height and body fat among player positions have not dramatically changed. Furthermore, the body mass index is not an accurate measure or representation of body fat or obesity in NFL players. These data provide a basic template for size profiles and differences among various positions and allow comparisons with other studies for changes in the NFL over the past 3 decades.     

Performance changes during a college playing career in NCAA division III football athletes

The purpose of this study was to compare anthropometric and athletic performance variables during the playing career of NCAA Division III college football players. Two hundred and eighty-nine college football players were assessed for height, body mass, body composition, 1-repetition-maximum (1RM) bench press, 1RM squat, vertical jump height (VJ), vertical jump peak, and vertical jump mean (VJMP) power, 40-yd sprint speed (40S), agility, and line drill (LD) over an 8-year period. All testing occurred at the beginning of summer training camp in each of the seasons studied. Data from all years of testing were combined. Players in their fourth and fifth (red-shirt year) seasons of competition were significantly (p < 0.05) heavier than first-year players. Significant increases in strength were seen during the course of the athletes' collegiate career (31.0% improvement in the 1RM bench press and 36.0% increase in squat strength). The VJ was significantly greater during the fourth year of competition compared to in the previous 3 years of play. Vertical jump peak and VJMP were significantly elevated from years 1 and 2 and were significantly higher during year 4 than during any previous season of competition. No significant changes in 40S or LD time were seen during the athletes playing career. Fatigue rate for the LD (fastest time/slowest time of 3 LD) significantly improved from the first (83.4 ± 6.4%) to second season (85.1 ± 6.5%) of competition. Fatigue rates in the fourth (88.3 ± 4.8%) and fifth (91.2 ± 5.2%) seasons were significantly greater than in any previous season. Strength and power performance improvements appear to occur throughout the football playing career of NCAA Division III athletes. However, the ability to significantly improve speed and agility may be limited.     

Positional physical characteristics of players drafted into the National Football League

To investigate the positional physical requirements necessary to be drafted into the National Football League (NFL), data from the annual NFL combine over the years 2005-2009 were examined. Only those players invited to the combine and subsequently drafted in the same year (n = 1,136) were included in the study. Data from 8 combine physical performance tests were examined for 15 positions. Combine measures evaluated for the center, cornerback, defensive end, defensive tackle, free safety, fullback, inside linebacker, offensive guard, offensive tackle, outside linebacker, quarterback, running back, strong safety, tight end, and wide receiver positions were the 9.1-, 18.3-, and 36.6-m sprints, the vertical and broad jumps, the 18.3-m shuttle run, the 3-cone drill, and the 102.1-kg bench press for maximum repetitions and, from this, a predicted measure of 1 repetition maximum. A 1-way analysis of variance detected differences in all 9 performance measures (p < 0.01). Post hoc independent t-tests indicated that over most tests many positions exhibited outcomes significantly different from most other positions. Generally, lineman positions performed inferiorly in sprint, jump and change-of-direction ability measures and superiorly in the upper body strength measures. Conversely, defensive back positions were the worst performers in the upper body strength test, and wide receivers and defensive backs were the best performers in all other measures. In general, offensive and defensive positions that commonly compete directly against one another display similar physical characteristics. Any advantages (statistically significant and not) between positions in direct competition were consistently in favor of defensive positions. The results of the present research present position-specific profiles for each of 15 positions. Coaches and practitioners will be able to use the findings of this research to better prepare athletes for entry into the NFL.     

Physical characteristics that predict functional performance in Division I college football players

Strength and conditioning professionals who work with collegiate football players focus much of their time and effort on developing programs to enhance athletic performance. Although there has been much speculation, there is little scientific evidence to suggest which combination of physical characteristics best predicts athletic performance in this population. The purpose of this investigation was to examine the relationship among 6 physical characteristics and 3 functional measures in college football players. Data were gathered on 46 NCAA Division I college football players. The 3 response variables were 36.6-m sprint, 18.3-m shuttle run, and vertical jump. The 6 regressor variables were height, weight, percentage of body fat, hamstring length, bench press, and hang clean. A stepwise multiple regression analysis was performed to screen for variables that predict physical performance. Regression analysis revealed clear prediction models for the 36.6-m sprint and 18.3-m shuttle run. The results of this investigation will help strength and conditioning specialists better understand the variables that predict athletic performance in Division I college football players.     

Heat acclimatization and hydration status of American football players during initial summer workouts

This investigation evaluated the new National Collegiate Athletic Association model of heat acclimatization for football players using physiological, psychological, fluid balance, anthropometric, and nutritional variables. Eleven football players (20 +/- 1 year, 1.88 +/- 0.05 m, and 115.36 +/- 18.85 kg) from a Division I football team were observed for the first 8 days of preseason practices. Measurements such as heart rate and gastrointestinal temperature (T(GI)) via telemetric sensor were taken before, 3 times during, and after practice daily. An average 1.39-kg (1.2%) decrease of body mass occurred from prepractice to postpractice (p < 0.01). Consistent with mild body mass losses, urinary indices of hydration status (i.e., color, specific gravity, and osmolality) indicated mild fluid deficits. A significant increase (p < 0.05) from pre- to postpractice was observed in urine color and urine specific gravity, but chronic hypohydration over the 8 days was not noted. The Environmental Symptoms Questionnaire (ESQ) postpractice score was significantly higher (p < 0.05) than the prepractice score was, but averages did not differ across practice days. There was no difference in postpractice T(GI) measurements across days (p < 0.05). Heart rate, T(GI), and ESQ measurements indicated that football players experienced gradual heat acclimatization and enhanced heat tolerance, despite progressive increases of exercise variables, clothing, and environmental stressors.     

Comparison of Olympic vs. traditional power lifting training programs in football players

Twenty members of an National Collegiate Athletic Association Division III collegiate football team were assigned to either an Olympic lifting (OL) group or power lifting (PL) group. Each group was matched by position and trained 4-days.wk(-1) for 15 weeks. Testing consisted of field tests to evaluate strength (1RM squat and bench press), 40-yard sprint, agility, vertical jump height (VJ), and vertical jump power (VJP). No significant pre- to posttraining differences were observed in 1RM bench press, 40-yard sprint, agility, VJ or in VJP in either group. Significant improvements were seen in 1RM squat in both the OL and PL groups. After log10-transformation, OL were observed to have a significantly greater improvement in Delta VJ than PL. Despite an 18% greater improvement in 1RM squat (p > 0.05), and a twofold greater improvement (p > 0.05) in 40-yard sprint time by OL, no further significant group differences were seen. Results suggest that OL can provide a significant advantage over PL in vertical jump performance changes.     

Effect of Olympic and traditional resistance training on vertical jump improvement in high school boys

The purpose of this study was to compare the effects of a ballistic resistance training program of Olympic lifts with those of a traditional resistance training program of power lifts on vertical jump improvement in male high school athletes. Twenty-seven male student athletes were recruited from a high school football program at a small, rural school in the Southeast. The subjects were divided into an Olympic training group (OT, n = 11), a power training group (PT, n = 10), and a control group (n = 6). Analysis of variance was used to determine whether a significant mean difference existed among groups on vertical jump improvement after 8 weeks of group-specific training. Effect size of vertical jump improvement between groups, and correlations between strength and vertical jump performance, were also examined. There was no significant mean difference (p >or= 0.05) among OT, PT, and control groups, but large effect sizes between OT and control (d = 1.06) and PT and control (d = 0.94) demonstrate that both OT and PT are effective in improving vertical jump performance in male high school athletes. Moderate to high correlations were noted between squat score and vertical jump after adjusting for body weight (r = 0.42) and between power clean and vertical jump after adjusting for body weight (r = 0.75). Findings from the current study indicate that Olympic lifts as well as power lifts provide improvement in vertical jump performance and that Olympic lifts may provide a modest advantage over power lifts for vertical jump improvement in high school athletes.