Acute effects of sodium citrate supplementation on competitive performance and lactate level of elite fitness challenge athletes: A crossover, placebo-controlled, double-blind study.

Purpose: The performance of sodium citrate has been investigated in high-intensity exercises, but fewer studies have addressed the role of citrate in weight-bearing exercises. Methods: Twenty fitness challenge athletes, aged 24-32 years, volunteered to participate in this crossover, placebo-controlled, double-blind study. Initially, ten athletes were given a placebo and asked to complete a fitness challenge (i.e., chin-ups, squat jumps, dips, walking lunges, sit-ups, and burpees-devil press). Another ten athletes were supplemented with sodium citrate 0.5 g/kg body mass supplements 3 h prior to performing the fitness challenges. The same procedures were completed two days later with the supplement and placebo dextrose groups switched in a cross-over design. Athletes and assessors were blinded for the experimental condition (placebo vs. verum). Lactate levels were measured 5 min after exercise. The athletes' performance on each item of the fitness challenge as well as their lactate levels, were compared. Differences between the means of the measured variables were contrasted using a dependent t-test. Results: Supplementing sodium citrate substantially improved athletes' performance in all six fitness challenge items (p < 0.05, 0.69

Effects of resistance training on body recomposition, muscular strength, and phase angle in older women with different fat mass levels.

AIMS: The concomitant increase in skeletal muscle mass (SMM) and decrease in fat mass has been termed body recomposition. This study aimed to analyze the influence of pre-training levels of fat mass on body recomposition, muscular strength, and (phase angle) PhA after 24 weeks of resistance training (RT) in older women. METHODS: Data from 99 older women (68.6 ± 5.7 years, 65.7 ± 8.6 kg, 155.1 ± 5.8 cm, 27.2 ± 3.1 kg/m2) was retrospectively analyzed. Participants were separated into tertiles according to the amount of fat mass at baseline as follows: low fat mass (L-FM, n = 33), moderate fat mass (M-FM, n = 33), and high fat mass (H-FM, n = 33). The participants underwent a RT program consisting of eight exercises, three sets per exercise, with a load between 8 and 15 RM, performed three times per week for 24 weeks. The SMM and fat mass were evaluated by dual-energy X-ray absorptiometry (DXA). Body recomposition was determined by the composite Z-score of changes in SMM and fat mass. One repetition maximum (1RM) tests in chest press, knee extension, and preacher curl were assessed to verify muscular strength. Bioimpedance was used to determine phase angle. RESULTS: Results indicated that after the RT period, a greater positive body recomposition was observed in the L-FM group than in M-FM and H-FM groups. Moreover, all groups increased muscular strength and phase angle with no significant difference among groups (P > 0.05). CONCLUSION: The present study results suggest that the initial amount of fat mass influences the body recomposition induced by RT in older women, with those with lower pre-training fat mass levels presenting higher levels of body recomposition. However, improvements in muscular strength and phase angle are not dependent on the amount of initial fat mass in older women.

Weaker older women gain more lower body strength than their stronger counterparts, but not muscle mass, following 12 weeks of resistance training.

We compared the magnitude of strength and muscle mass changes in response to resistance training (RT) between stronger older women and their weaker counterparts. Older women (n = 207) were grouped into tertiles according to their baseline muscular strength index. The upper and lower tertiles participants were categorized as stronger (STR, n = 69) and weaker (WKR, n = 69), respectively. Both groups engaged in a 12-week whole-body RT program. Outcomes included one-repetition maximum (1RM) tests in the three lifts and assessment of segmental lean soft tissue (LST) and skeletal muscle mass (SMM). The 1RM increase was similar between groups for the chest press [between-groups effect size of the differences (ESdiff) and 95% confidence interval (95%CI) = 0.10 (95%CI: -0.52, 0.31), P = 0.617] and preacher curl [ESdiff = 0.08 (95%CI: -0.48, 0.32), P = 0.681]. Changes were greater in WKR than STR for 1RM leg extension [ESdiff = -0.45 (95%CI: -0.86, -0.04), P = 0.030]. The increases of segmental LST and SMM were similar between-groups (ESdiff contains zero, P ≥ 0.434). We conclude that stronger and weaker older women benefit similarly for muscle mass and upper-limb strength gains. Notably, weaker older women may experience greater lower-limbs strength gains.

Momentum, Rather Than Velocity, Is a More Effective Measure of Improvements in Division IA Football Player Performance.

ABSTRACT: Mann, JB, Mayhew, JL, Dos Santos, ML, Dawes, JJ, and Signorile, JF. Momentum, rather than velocity, is a more effective measure of improvements in Division IA football player performance. J Strength Cond Res 36(2): 551-557, 2022-Speed, or the time to complete straight runs or agility drills, is commonly used to assess performance in collegiate American football players. However, it is common for players' speeds to plateau by the second year of eligibility, whereas their body masses continue to increase. The purpose of this study was to track change in speed, body mass, and momentum (body mass · velocity), across Division 1 football players' 4-year careers (n = 512). Complete data were derived for the 40-yd sprint (n = 82), the proagility shuttle (n = 73), and the L drill (n = 73) from the same NCAA Division 1 team over a 15-year period. Significant changes were seen for velocity between year 1 and the next 3 playing years (p < 0.05), with no differences between years 2 and 4, whereas body mass increased significantly across all playing years (p < 0.05). Further momentum increased across all years for all tests (p < 0.0001). These results indicate the importance of including changes in body mass when evaluating performances during sprints and change of direction drills. Our results also suggest that using sprint or agility drill times to evaluate playing potential across football players' collegiate careers may be ineffective and can provide players with a false and disheartening picture of their improvements across their careers. Momentum, which incorporates training-induced increases in both speed and body mass, would be a more relevant and supportive measure of players' improvements. In addition, the simple computation of this variable, using existing speed and body mass data, may be an important addition to the National Football League combine as a measure of playing potential in the professional game.

Comparison of 2 Weekly Frequencies of Resistance Training on Muscular Strength, Body Composition, and Metabolic Biomarkers in Resistance-Trained Older Women: Effects of Detraining and Retraining.

ABSTRACT: Amarante do Nascimento, M, Nunes, JPA, Pina, FLC, Ribeiro, AS, Carneiro, NH, Venturini, D, Barbosa, DS, Mayhew, JL, and Cyrino, ES. Comparison of 2 weekly frequencies of resistance training on muscular strength, body composition, and metabolic biomarkers in resistance-trained older women: Effects of detraining and retraining. J Strength Cond Res 36(5): 1437-1444, 2022-This study aimed to compare the effects of 2 weekly frequencies of resistance training (RT) on muscular strength, body composition, and metabolic biomarkers in previously resistance-trained older women after detraining and retraining. Forty subjects (>60 years) performed RT (8 exercises, 1 set of 10-15 repetitions maximum) 2 (G2x) or 3 (G3x) times per week over 12 weeks of training and retraining. After training, subjects were detrained for 12 weeks. After detraining, there were significant decreases (p < 0.05) in upper-body (∼12%) and lower-body (∼14%) muscular strength, fat-free mass (FFM) (∼2%), and testosterone (∼26%), whereas increases were revealed for fat mass (FM) (∼4%), relative body fat (∼3%), fasting glucose (∼8%), low-density lipoprotein cholesterol (LDL-C) (∼21%), and triglycerides (∼24%), with no differences between groups (p > 0.05). Following retraining, there were significant increases (p < 0.05) for upper (∼7%) and lower (∼10%) muscular strength, FFM (∼2%), and testosterone (∼20%). In contrast, decreases were found for FM (∼7%), relative body fat (∼3%), fasting glucose (∼6%), LDL-C (∼14%), and triglycerides (∼21%), also with no differences between groups (p > 0.05). Gains after retraining were lower than after training (p < 0.05) only for upper- and lower-body muscular strength (∼6%) and testosterone (∼11%). Total cholesterol, high-density lipoprotein cholesterol, IGF-1, and C-reactive protein did not change at any point in the study for either group (p > 0.05). Our results suggest that older women can regain previous RT program benefits following detraining, regardless of the weekly training frequency. However, some fitness components may take longer to reestablish than the initial training level.

Differential Responsiveness for Strength Gain Between Limbs After Resistance Training in Older Women: Impact on Interlimb Asymmetry Reduction.

ABSTRACT: Nunes, JP, Marcori, AJ, Ribeiro, AS, Cunha, PM, Kassiano, W, Costa, BDV, Aguiar, AF, Nakamura, M, Mayhew, JL, and Cyrino, ES. Differential responsiveness for strength gain between limbs after resistance training in older women: Impact on interlimb asymmetry reduction. J Strength Cond Res 36(11): 3209-3216, 2022-The present study compared strength responses between preferred (PREF) and nonpreferred (N-PREF) legs in older women. Muscular strength was measured unilaterally using an isokinetic dynamometer and was analyzed for reproducibility scores, acute performance, and responsiveness to a resistance training (RT) program. One hundred eleven women (aged ≥60 years) performed 12 weeks of whole-body RT (3 times a week; 4 lower-body exercises). Reproducibility scores (intraclass correlation coefficient ≥0.920; following test-retests in part of the sample at pretraining; n = 19), average acute performances, and average strength gains (PREF = ∼6.9%; N-PREF = ∼7.2%) were similar between legs (p > 0.05). However, the individual analyses showed that some subjects were considered responders to strength gains in 1 leg, whereas nonresponders in the other. Nonetheless, when considering the responses in all strength tests, most subjects (91%) were considered responder to at least 1 measure. In addition, it was observed that the strength ratio between PREF/N-PREF legs was altered for those who presented some asymmetry at baseline, as the limbs became more symmetrical in all strength measures after the RT. In conclusion, we observed that some older women may have different levels of strength between legs; however, a traditional 12-week RT program with bilateral exercises can reduce such asymmetry by inducing greater strength gains in the weaker leg.

Responsiveness to muscle mass gain following 12 and 24 weeks of resistance training in older women.

BACKGROUND: Many factors may influence the magnitude of individual responses to resistance training (RT). How the manipulation of training volume and frequency affects responsiveness level for muscle mass gain in older women has not been investigated. AIMS: This study had the objective of identifying responders (RP) and non-responders (N-RP) older women for skeletal muscle mass (SMM) gain from a 12-week resistance training (RT) program. Additionally, we analyzed whether the N-RP could gain SMM with an increase in weekly training volume over 12 additional weeks of training. METHODS: Thirty-nine older women (aged ≥ 60 years) completed 24 weeks of a whole-body RT intervention (eight exercises, 2-3×/week, 1-2 sets of 10-15 repetitions). SMM was estimated by DXA, and the responsive cut-off value was set at two times the standard error of measurement. Participants were considered as RP if they exceeded the cut-off value after a 12-week RT phase, while the N-RP were those who failed to reach the SMM cut-off. RESULTS: Of the 22 participants considered to be N-RP, only 3 accumulated SMM gains (P = 0.250) that exceeded the cut-off point for responsiveness following 12 additional weeks of training, while 19 maintained or presented negative SMM changes. Of the 17 participants considered to be RP, all continued to gain SMM after the second 12-week RT phase. No significant correlation was observed between the changes in SMM and any baseline aspect of the participants. CONCLUSIONS: Our results suggest that some older women are RP, while others are N-RP to SMM gains resulting from RT. Furthermore, the non-responsiveness condition was not altered by an increase of training volume and intervention duration while RP participants continue to increase SMM; it appears that RP continue to be RP, and N-RP continue to be N-RP.

Prediction of Anaerobic Power From Standing Long Jump in NCAA Division IA Football Players.

ABSTRACT: Mann, JB, Bird, M, Signorile, JF, Brechue, WF, and Mayhew, JL. Prediction of anaerobic power from standing long jump in NCAA Division IA football players. J Strength Cond Res 35(6): 1542-1546, 2021-Despite the popularity of the standing long jump (SLJ), limited research has explored the estimation of power developed during this test. The purpose of this study was to determine SLJ power from jump distance and selected anthropometric measures in NCAA Division IA football players. Height (Ht), body mass (Wt), thigh length, and lower leg length (LL) were measured in 58 players, allowing calculation of leg ratios of thigh length·Ht-1, LL·Ht-1, and TL·SL-1. Players performed 2-3 maximal familiarization trials of SLJ followed by 2 maximal jumps from a 3-dimension force plate sampling at 1,000 Hz. Standing long jump distance (intraclass correlation coefficient [ICC] = 0.944) and power (ICC = 0.926) calculated from resultant force and velocity vectors were highly reliable. Standing Ht (r = 0.40), Wt (r = 0.36), lower leg length (r = 0.43), total leg length (thigh + LLs) (r = 0.38), and best SLJ (r = 0.52) were significantly related (p < 0.05) to peak power, but none accounted for more than 27% of the common variance. Step-wise multiple regression identified SLJ and body mass as the only significant variables necessary to predict peak power (Power [W] = 32.49·SLJ [cm] + 39.69·Wt [kg] - 7,608, R = 0.86, SEE = 488 W, CV% = 9.3%). Standing long jump contributed 56.8% to the known variance, whereas Wt contributed 43.2%. Thus, a combination of SLJ and Wt can be used to effectively estimate explosive power in Division IA college football players.

Relationship of Barbell and Dumbbell Repetitions With One Repetition Maximum Bench Press in College Football Players.

ABSTRACT: Heinecke, ML, Mauldin, ML, Hunter, ML, Mann, JB, and Mayhew, JL. Relationship of barbell and dumbbell repetitions with one repetition maximum bench press in college football players. J Strength Cond Res 35(2S): S66-S71, 2021-Dumbbell training to augment barbell training is gaining popularity. However, information is lacking that details the compatibility of strength and endurance between dumbbell and barbell performances in the same exercise. Therefore, the purposes of this study were to compare the similarity of muscular endurance performance between dumbbell and barbell exercises and to assess the accuracy of predicting one repetition maximum (1RM) barbell bench press from barbell and dumbbell repetitions to fatigue (RTF). College football players (n = 40) performed 1RM barbell bench press and RTF with a 90.9-kg barbell. On separate days, unilateral (45.5 kg) and bilateral dumbbell (90.9 kg) RTF were performed. Barbell RTF (13.8 ± 9.2) were significantly greater (effect size [ES] = 0.14) than bilateral dumbbell RTF (12.5 ± 9.5) but highly correlated (r = 0.96). Unilateral dumbbell RTF were significantly greater (ES = 0.13) for dominant hand (10.8 ± 10.1) than nondominant hand (9.5 ± 9.7) but highly correlated (r = 0.97). Prediction of 1RM barbell bench press was equally effective using a constant weight barbell (r = 0.90) or equivalent weight bilateral dumbbells (r = 0.87) with total errors of 7.3 and 8.2%, respectively. Barbell and dumbbell repetitions with equivalent weights place a similar demand on the upper-body musculature for training and testing purposes in football athletes.

Comparision of Low and High Volume of Resistance Training on Body Fat and Blood Biomarkers in Untrained Older Women: A Randomized Clinical Trial.

ABSTRACT: Cunha, PM, Tomeleri, CM, Nascimento, MA, Mayhew, JL, Fungari, E, Cyrino, LT, Barbosa, DS, Venturini, D, and Cyrino, ES. Comparision of low and high volume of resistance training on body fat and blood biomarkers in untrained older women: a randomized clinical trial. J Strength Cond Res 35(1): 1-8, 2021-The purpose of this study was to compare the effects of resistance training (RT) performed with 2 different volumes on body fat and blood biomarkers in untrained older women. Sixty-five physically independent older women (≥60 years) were randomly assigned to one of 3 groups: low-volume (LV) training group, high-volume (HV) training group, and a control group. Both training groups performed RT for 12 weeks, using 8 exercises of 10-15 repetitions maximum for each exercise. The low-volume group performed only a single set per exercise, whereas the HV group performed 3 sets. Anthropometric, body fat (%), trunk fat, triglycerides (TG), total cholesterol, low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol, very LDL-c (VLDL-c), glucose (GLU), C-reactive protein (CRP), and composite Z-score were measured. The HV group obtained greater improvements compared with the LV group (p < 0.05) for TG (LV = -10.5% vs. HV = -16.6%), VLDL-c (LV = -6.5% vs. HV = -14.8%), GLU (LV = -4.7% vs. HV = -11.1%), CRP (LV = -13.2% vs. HV = -30.8%), % body fat (LV = -2.4% vs. HV = -6.1%), and composite Z-score (LV = -0.13 ± 0.30 vs. HV = -0.57 ± 0.29). Trunk fat was reduced (p < 0.05) only in the HV group (-6.8%). We conclude that RT performed in higher volume seems to be the most appropriate strategy to reduce body fat (%), trunk fat, improve blood biomarkers, and reduce composite Z-score in older women.

Agreement Between Bioelectrical Impedance and Dual-Energy X-Ray Absorptiometry to Track Changes in Fat-Free Mass After Resistance Training in Older Women.

Nascimento, MA, Silva, DRP, Ribeiro, AS, Pina, FLC, Gerage, AM, Gobbo, LA, Mayhew, JL, and Cyrino, ES. Agreement between bioelectrical impedance and dual-energy x-ray absorptiometry to track changes in fat-free mass after resistance training in older women. J Strength Cond Res 34(6): 1700-1708, 2020-The aim of our study was to compare the agreement between bioelectrical impedance (BIA) and dual-energy X-ray absorptiometry (DXA) to track changes on fat-free mass (FFM) after a resistance training (RT) program in older women. Forty-three older women (65.2 ± 4.6 years, 59.5 ± 9.2 kg, 156.4 ± 6.0 cm, 24.3 ± 3.3 kg·m) participated in a RT intervention (12 weeks, 8 exercises, 2 sets, 10-15 repetitions, 3 nonconsecutive days per week). Fat-free mass changes were determined by a single-frequency BIA device (EQ1), 6 BIA prediction equations for older women (EQ2, EQ3, EQ4, EQ5, EQ6, and EQ7), and DXA. At pretraining, 3 equations overpredicted, and 3 underpredicted DXA FFM (F = 244.63, p < 0.001), although all equations had high correlations with DXA (r = 0.78-0.83). After training, 4 equations overpredicted and one underpredicted DXA FFM (F = 176.25, p < 0.001). Dual-energy X-ray absorptiometry detected significant gains in FFM (0.65 ± 0.82 kg; p < 0.05), as did EQ3 (0.55 ± 1.69 kg; p < 0.05), and EQ4 (0.61 ± 1.88 kg; p < 0.05), whereas the remaining equations did not indicate significant changes in FFM. Low correlations between FFM and equation change values suggest that single-frequency BIA-derived equations may not provide sufficient accuracy to track changes in FFM after 12 weeks of RT in older women.

Effects of Different Resistance Training Frequencies on Fat in Overweight/Obese Older Women.

AIM: This study compared the effect of different resistance training (RT) frequencies on total, android, gynoid and trunk body fat in overweight/obese older women. METHODS: Fifty-seven overweight/obese older women (66.9±5.3 years and 39.9±4.9% body fat) were randomly assigned to one of three groups: a group performing RT twice a week (G2X), a group performing RT three times a week (G3X), or a non-exercise control group (CG). Both training groups performed the same 12-week RT program consisting of 8 exercises that trained all major muscle groups. Dual-energy X-ray absorptiometry was used to assess body composition. RESULTS: After the intervention period, both G2X and G3X demonstrated significant (P<0.05) reductions in adiposity compared to the CG for total body fat (G2X=-1.7%, G3X=-2.7%, CG=+2.1%), android fat (G2X=-6.2%, G3X=-7.0%, CG=+8.6%), gynoid fat (G2X=-2.5%, G3X=-2.9%, CG=+1.0%), and trunk fat (G2X=-2.5%, G3X=-3.0%, CG=+2.9%), with no significant differences between training groups. CONCLUSION: These results demonstrate that a low-volume 12-week RT program performed two or three times per week causes decreases in total and regional fat deposition with the greatest reductions occurring in the android region.

Improvement of cellular health indicators and muscle quality in older women with different resistance training volumes.

The main purpose of this study was to compare the effects of resistance training (RT) performed with different training volumes on phase angle (PhA), body water components, and muscle quality (MQ) in untrained older adult women. A second purpose was to assess the relationship between PhA and MQ. Sixty-two older adult women (68.6 ± 5.0 years, 65.2 ± 13.3 kg, 156.1 ± 6.2 cm) were randomly assigned into one of the three groups: two training groups performed either 1 set (G1S) or 3 sets (G3S), or a control group (CG). Body water components and PhA were estimated by bioelectrical impedance (BIA). MQ was determined by dividing skeletal muscle mass estimated by dual-energy absorptiometry (DXA) by total muscle strength from three exercises. After the intervention period, both training groups demonstrated improvements (P < 0.05) when compared with CON for intracellular water, total body water, PhA, and MQ. These results suggest that RT can improve PhA, body water components, and MQ after 12 weeks of RT in untrained older women, regardless of training volume. Furthermore, changes in MQ were positively correlated with changes in PhA (r = 0.60, P < 0.01).

Chronic Blood Pressure Reductions and Increments in Plasma Nitric Oxide Bioavailability.

This study analyzed the effects of 12 weeks of resistance training (RT) on resting blood pressure (BP) and plasma levels of nitric oxide metabolites (NOx) in pre- and hypertensive older women, and evaluated the relationship between these 2 parameters. Thirty-five older women (68.2±5.7 years, 70.0±14.4 kg, 157.1±6.4 cm, 28.3±5.0 kg.m-2) were randomly allocated into a training group (TG; n=17), which performed a 12-week RT program, and a control group (CG; n=18), which did not perform any physical exercise. Anthropometry, one repetition maximum (1RM), body composition analysis by dual energy X-ray absorptiometry, blood samples, and resting BP were measured. There was a significant interaction for all variables analyzed, in which reductions of systolic BP (-8.5%), diastolic BP (-8.4%), and mean arterial pressure (-8.5%), and increases of NOx (+35.2%) were observed only for the TG. Moreover, a negative and significant correlation was observed (P<0.05; r=-0.63) between NOx and systolic BP in the TG. Results suggest that a 12-week RT program is sufficient to induce reductions in BP in pre- and hypertensive older women and that the decrease in systolic BP is associated with an increase in plasma NOx concentration.

Fat-Free Mass Index in NCAA Division I and II Collegiate American Football Players.

Fat-free mass index (FFMI) is a height-adjusted assessment of fat-free mass (FFM), with previous research suggesting a natural upper limit of 25 kg·m in resistance trained male athletes. The current study evaluated upper limits for FFMI in collegiate American football players (n = 235) and evaluated differences between positions, divisions, and age groups. The sample consisted of 2 National Collegiate Athletic Association Division I teams (n = 78, n = 69) and 1 Division II team (n = 88). Body composition was assessed via dual-energy x-ray absorptiometry and used to calculate FFMI; linear regression was used to normalize values to a height of 180 cm. Sixty-two participants (26.4%) had height-adjusted FFMI values above 25 kg·m (mean = 23.7 ± 2.1 kg·m; 97.5th percentile = 28.1 kg·m). Differences were observed among position groups (p < 0.001; η = 0.25), with highest values observed in offensive linemen (OL) and defensive linemen (DL) and lowest values observed in offensive and defensive backs. Fat-free mass index was higher in Division I teams than Division II team (24.3 ± 1.8 kg·m vs. 23.4 ± 1.8 kg·m; p < 0.001; d = 0.49). Fat-free mass index did not differ between age groups. Upper limit estimations for FFMI seem to vary by position; although the 97.5th percentile (28.1 kg·m) may represent a more suitable upper limit for the college football population as a whole, this value was exceeded by 6 linemen (3 OL and 3 DL), with a maximal observed value of 31.7 kg·m. Football practitioners may use FFMI to evaluate an individual's capacity for additional FFM accretion, suitability for a specific position, potential for switching positions, and overall recruiting assessment.

Relationship Between Agility Tests and Short Sprints: Reliability and Smallest Worthwhile Difference in National Collegiate Athletic Association Division-I Football Players.

The Pro-Agility test (I-Test) and 3-cone drill (3-CD) are widely used in football to assess quickness in change of direction. Likewise, the 10-yard (yd) sprint, a test of sprint acceleration, is gaining popularity for testing physical competency in football players. Despite their frequent use, little information exists on the relationship between agility and sprint tests as well the reliability and degree of change necessary to indicate meaningful improvement resulting from training. The purpose of this study was to determine the reliability and smallest worthwhile difference (SWD) of the I-Test and 3-CD and the relationship of sprint acceleration to their performance. Division-I football players (n = 64, age = 20.5 ± 1.2 years, height = 185.2 ± 6.1 cm, body mass = 107.8 ± 20.7 kg) performed duplicate trials in each test during 2 separate weeks at the conclusion of a winter conditioning period. The better time of the 2 trials for each week was used for comparison. The 10-yd sprint was timed electronically, whereas the I-Test and 3-CD were hand timed by experienced testers. Each trial was performed on an indoor synthetic turf, with players wearing multicleated turf shoes. There was no significant difference (p > 0.06) between test weeks for the I-Test (4.53 ± 0.35 vs. 4.54 ± 0.31 seconds), 3-CD (7.45 ± 0.06 vs. 7.49 ± 0.06 seconds), or 10-yd sprint (1.85 ± 0.12 vs. 1.84 ± 0.12 seconds). The intraclass correlation coefficients (ICC) for 3-CD (ICC = 0.962) and 10-yd sprint (ICC = 0.974) were slightly higher than for the I-Test (ICC = 0.914). These values lead to acceptable levels of the coefficient of variation for each test (1.2, 1.2, and 1.9%, respectively). The SWD% indicated that a meaningful improvement due to training would require players to decrease their times by 6.6% for I-Test, 3.7% for 3-CD, and 3.8% for 10-yd sprint. Performance in agility and short sprint tests are highly related and reliable in college football players, providing quantifiable parameters for judging true change in performance as opposed to random measurement variation in college football players.

Validity and reliability of hand and electronic timing for 40-yd sprint in college football players.

The 40-yd sprint is the premier event for evaluating sprint speed among football players at all competitive levels. Some questions remain concerning the validity of hand timing compared with electronic timing, as well as the lack of assessment and reliability of each method. The purpose of this study was to evaluate the validity of hand timing by experienced and novice timers compared with electronic timing and to establish the reliability and smallest worthwhile difference (SWD) of each method for the 40-yd sprint. National Collegiate Athletic Association (NCAA) Division I college football players (n = 81) ran two 40-yd sprint trials, with each being timed electronically (touch pad start and infrared beam stop) and with hand-held stopwatches by 2 experienced and 4 novice timers. There was no significant difference between trials timed electronically or by experienced and novice timers. Hand timing (experienced = 4.90 ± 0.34 seconds; novice = 4.86 ± 0.33 seconds) produced a significantly faster 40-yd sprint time than electronic timing (5.12 ± 0.35 seconds) by 0.22 ± 0.07 and 0.26 ± 0.08 seconds, respectively. Relative reliability was extremely high for all comparisons with intraclass correlation coefficient >0.987. The SWD was 0.12 seconds with electronic timing and 0.14 seconds with hand timing. In conclusion, hand timing produces faster sprint times than electronic timing in college football players, independent of timer experience. Repeated 40-yd sprint trials have high relative reliability regardless of timing method. A meaningful change in 40-yd sprint performance is dependent on timing method used.

Efficacy of the National Football League-225 Test to Track Changes in One Repetition Maximum Bench Press After Training in National Collegiate Athletic Association Division IA Football Players.

Numerous investigations have attested to the efficacy of the National Football League (NFL)-225 test to estimate one repetition maximum (1RM) bench press. However, no studies have assessed the efficacy of the test to track changes in strength across a training program. The purpose of this study was to determine the accuracy of the NFL-225 test for determining the change in 1RM bench press in National Collegiate Athletic Association Division IA college football players after training. Over a 4-year period, players (n = 203) were assessed before and after a 6-week off-season resistance program for 1RM bench press and repetitions completed with 102.3 kg (225 lbs). Test sessions typically occurred within 1 week of each other. Players significantly increased 1RM by 4.2 ± 8.6 kg and NFL-225 repetitions by 0.9 ± 2.3, although the effect size (ES) for each was trivial (ES = 0.03 and 0.07, respectively). National Football League 225 prediction equations had higher correlations with 1RM before training (intraclass correlation coefficient [ICC] = 0.95) than after training (ICC = 0.75). The correlation between the change in NFL-225 repetitions and change in 1RM was low and negative (r = -0.22, p < 0.02). Short-term heavy resistance training may alter the association between muscular strength and muscular endurance in college football players and render the NFL-225 test less effective in predicting the change in 1RM bench press strength after short-term training.

Reliability and smallest worthwhile difference of the NFL-225 test in NCAA Division I football players.

The NFL-225 test is widely used to assess the strength level and evaluate the progress of college football players during resistance training. Despite the studies evaluating the validity of this test, there are no reports assessing its reliability. The purpose of this study was to determine the reliability and smallest worthwhile difference (SWD) of the NFL-225 test in Division I college football players. Seventy-two players were assessed for more than 3 weeks for the number of repetitions completed with a constant load of 102.3 kg (225 lbs) during winter conditioning. Test sessions occurred on the same day and at the same time 1 week apart. Intraclass correlation coefficients (ICCs) between weeks 1 and 2 (ICC = 0.987), weeks 2 and 3 (ICC = 0.981), and across weeks 1, 2, and 3 (ICC = 0.988) indicated high relative reliability. A small technical error (TE) (TE = 0.5 repetitions) provided strong absolute reliability. The SWD suggests that a change in performance of 3 repetitions or more after training would indicate a meaningful improvement in performance for this test.

Factors that contribute to and account for strength and work capacity in a large cohort of recreationally trained adult healthy men with high- and low-strength levels.

The factors that best account for differences in strength across all types of exercise, body types, and training histories are not well understood. The purpose of this study was to assess the effects of strength level and body composition on upper- and lower-body work capacity in adult men. From a cohort of 295 adult men (25.6 ± 7.5 years, 178 ± 8 cm, 85.2 ± 15 kg), low-strength (LS, n = 72) and high-strength (HS, n = 66) samples were selected based on 1 repetition maximum (1RM) bench press (BP) and leg strength (LP) values. Work capacity for each exercise was determined from the product of repetition weight (80% 1RM) and maximum repetitions-to-fatigue (RTF). Body composition was measured using dual-energy x-ray absorptiometry. The HS group was significantly greater than the LS group in total body mass and fat-free mass but not in age, height, fat mass, or %fat. Low-strength and HS groups were not significantly different (p > 0.05) in RTF for either BP (8.7 ± 3.1 vs. 8.3 ± 1.9 reps, respectively) or LP (15.6 ± 7.6 vs. 17.0 ± 6.3 reps, respectively), making the ratio of RTF for BP vs. LP nonsignificant (LS = 2.0 ± 1.0; HS = 2.2 ± 0.9). The HS group produced significantly greater (p < 0.001) absolute and relative work capacities for both BP and LP compared with the LS group. Repetitions-to-fatigue had a greater influence on BP (r2 = 0.74) and LP (r2 = 0.85) work capacities in the LS group than did RepWt (r2 = 0.07 and 0.28, respectively). In the HS group, RTF (r2 = 0.79) had a greater influence than RepWt (r2 = 0.10) on BP work capacity, whereas the 2 components were more similar for LP work capacity (r2 = 0.64 and 0.47, respectively). When evaluated at the same %1RM, muscular endurance is similar across divergent strength levels meaning that work capacity (load × reps) will be greater for HS individuals. Controlling for the influence of body composition variables (e.g., fat or fat-free mass) does not eliminate the difference in work capacity between strength groups suggesting that other factors are accounting for strength expression. Prescribing repetitions against a fixed relative load is largely dependent on exercise type and must be considered by strength and conditioning professionals.