Effect of Extreme Volume-Load Differences for a Single Unilateral Exercise During In-Season Resistance Training on Measures of Bilateral Strength, Power, and Speed in Collegiate American Football Players.

ABSTRACT: Crawley, K, Adams, KJ, DeBeliso, M, and Lawrence, MM. Effect of extreme volume-load differences for a single unilateral exercise during in-season resistance training on measures of bilateral strength, power, and speed in collegiate american football players. J Strength Cond Res 38(1): 80-89, 2024-This study examined the impact extreme volume-load differences for a single weekly exercise, when all other exercises' volume loads were similar, would have on American football performance variables after in-season resistance training (RT). Twenty male National Collegiate Athletic Association (NCAA) American footballers (18-23 years, 98.4 ± 19.3 kg) were randomly assigned to an extreme high-volume low-intensity (EHVLI; n = 11) group or a low-volume high-intensity (LVHI; n = 9) group. Subjects performed the same evidence-based RT exercises and volume loads for 8 weeks thrice weekly, with the only differences being once weekly unilateral reverse dumbbell lunge (EHVLI) or unilateral Hatfield safety bar back squat (LVHI) exercises performed with different volume loads. Performance variables were assessed 1 week before (PRE) and after (POST) 8 weeks of RT. A 2-way analysis of variance with repeated measures and the Sidak post hoc test were used ( p < 0.05). Extreme high-volume low-intensity had no significant ( p > 0.05) PRE-to-POST RT changes in muscular strength in 1 repetition maximum (251.8 ± 48.7 to 274.6 ± 61.3 kg) or power in vertical jump (79.2 ± 8.8 to 78.2 ± 10.8 cm). Conversely, LVHI had significant ( p < 0.05) PRE-to-POST RT improvements in strength (249.2 ± 54.4 to 284.1 ± 55.0 kg) and power (72.8 ± 11.4 to 76.3 ± 10.0 cm). Furthermore, LVHI vs. EHVLI displayed significantly greater percentage difference increases from PRE values in muscular power (6.7% ± 7.2 vs. -1.3% ± 6.0, respectively), with no significant differences between groups (LVHI vs. EHVLI) in muscular strength (8.8% ± 3.1 vs. 6.7% ± 8.0, respectively) and 10-yard acceleration (2.2% ± 5.6 vs. 3.2% ± 5.6, respectively). For in-season RT of strength and power in collegiate American football players, all exercises performed should use evidence-based volume loads to optimize adaptations because a single exercise performed with extreme volume load may limit muscular strength and power development.

The Relationship Between Partial and Full Range of Motion Deadlift 1-Repetition Maximum: A Technical Note.

ABSTRACT: Gillingham, B, Bishop, A, Higa, GK, Adams, KJ, and DeBeliso, M. The relationship between partial and full range of motion deadlift 1-repetition maximum: a technical note. J Strength Cond Res 37(4): 909-914, 2023-The full range of motion (FROM) or partial range of motion (PROM) deadlift (DL) are often included in resistance training (RT) programs and are performed by strength athletes in competition. This study examined the relationship between the FROM and PROM 1-repetition maximum (1RM) DL and if the PROM 1RM DL can be estimated by the FROM 1RM DL. Eighteen National Collegiate Athletic Association wrestlers (20.8 ± 1.2 years, 176.0 ± 5.2 cm, 78.9 ± 10.6 kg) performed a warm-up followed by the assessment of the FROM and PROM 1RM DLs. The FROM DLs were executed with a starting position of the bar resting on the lifting platform. Partial range of motion DLs were executed in a power rack with the bar starting position at ≈2.54 cm above the patella. Regression analysis was employed to estimate PROM 1RM DL based on FROM 1RM DL, body height, and mass. A Pearson's correlation coefficient ( r ) was used to compare the PROM 1RM DL with FROM 1RM DL. A dependent t test was used to compare the PROM 1RM DL and FROM 1RM DL scores (α < 0.05). The PROM 1RM DL scores (226.0 ± 40.6 kg) were significantly greater than the FROM 1RM DL scores (191.7 ± 37.2 kg) ( p < 0.05: effect size = 0.92). The PCC between the PROM and FROM 1RM DL was r = 0.85 ( p < 0.05). The regression coefficient for the FROM 1RM DL was significant ( p < 0.05; R = 0.85, R2 = 0.73). The regression coefficients for body mass and height were not significant ( p > 0.05). The PROM and FROM DL may be interchangeable modalities within an RT program, and the PROM 1RM DL can be accurately predicted by the FROM 1RM DL.

Reliability and Criterion Validity of the Assess2Perform Bar Sensei.

The Assess2Perform Bar Sensei is a device used to measure barbell velocity for velocity-based training that has not yet been validated. The purpose of this study was to determine criterion validity and reliability of the Assess2Perform Bar Sensei in barbell back squats by comparing it against the GymAware PowerTool, a previously validated instrument. Sixteen injury-free, resistance-trained subjects (eleven males and five females) were recruited. Subjects were tested for their back squat one repetition maximum (1RM). Then, on two separate days, subjects performed two sets of three repetitions at loads of 45%, 60% and 75% 1RM. The GymAware PowerTool and Bar Sensei were attached to the barbell in similar locations for concurrent collection of mean concentric velocity (MCV) and peak concentric velocity (PCV). The Bar Sensei and PowerTool showed generally fair to poor agreement for MCV and PCV when subjects lifted 45% of 1RM (intraclass correlation;ICC 0.4-0.59), and they showed poor agreement when subjects lifted 60% and 75% of 1RM (ICC 0.3-0.4). Inter-repetition/within-set reliability for the Bar Sensei ranged between ICC = 0.273-0.451 for MCV and PCV compared to the far more reliable PowerTool (ICC = 0.651-0.793). Currently, the Bar Sensei is not a reliable or valid tool for measuring barbell velocity in back squats.

Optimal Timing for Post-Activation Potentiation in Women Collegiate Volleyball Players.

Post-activation potentiation (PAP) has been shown to acutely amplify muscular power output and may be advantageous for athletes looking to improve performance. PAP may have an acute window of effectiveness between 2 to 20 min. With correct timing and implementation it may be possible to induce PAP in competitive situations. The purpose of this study was to examine the time frame of potentiation following a PAP warm-up in collegiate female volleyball players. In this study, nine female collegiate volleyball players completed three laboratory sessions over the course of 10 days. During the first session, the athlete's 5-RM back squat was determined for subsequent use as the conditioning activity to initiate PAP. A repeated measures experimental design was then employed for Sessions 2 and 3 where half of the participants alternately performed either a dynamic or PAP warm-up prior to performing a standing long jump (SLJ) at 2, 6, 10, 14, and 18 min. A mixed-factor repeated measures ANOVA was used to determine the effects of the two warm-up strategies (PAP vs. dynamic) on standing long jump (SLJ) performance across time. There was a significant effect for time (p < 0.01) and warm-up strategy (p < 0.01). Bonferroni post hoc techniques determined that the SLJs that followed the PAP warm-up were significantly greater at 2 (4.8%), 6 (3.6%), and 10 (3.6%) min compared to SLJs post-dynamic warm-up (p < 0.05). However, those differences did not persist at 14 or 18 min (p > 0.05). Further analysis included non-parametric pairwise comparisons (Wilcoxon signed-rank tests) between the SLJ scores at 2, 6, 10, 14, and 18 min (PAP vs. dynamic). The non-parametric results were consistent with the parametric results. Within the parameters of this study, it is concluded that performing a 5-RM back squat induces a measureable PAP effect for up to 10 min.

Comparing one repetition maximum and three repetition maximum between conventional and eccentrically loaded deadlifts.

This study determined if an eccentrically loaded deadlift yields a higher 1 repetition maximum (1RM) and 3RM than a conventional deadlift and if the 1RM conventional and eccentrically loaded deadlift can be accurately estimated from the 3RM (3RM = 93% of 1RM). Division 1 football players (n = 15; 20.3 ± 1.9 years; 95.8 ± 18.2 kg; 184.4 ± 6.6 cm) participated. Deadlift 1RM and 3RM were measured in the conventional and eccentrically loaded deadlift. Dependent t-tests showed no significant difference between the 3RM and 1RM conventional deadlift and the 3RM and 1RM eccentrically loaded deadlift (p = 0.30 and p = 0.20, respectively). Pearson correlation between the 1RM conventional deadlift estimate and 1RM conventional deadlift actual was r = 0.91 (p ≤ 0.01); a dependent t-test indicated the 1RM conventional deadlift estimate was significantly less than the 1RM conventional deadlift actual (p = 0.007). Pearson correlation between the 1RM eccentrically loaded deadlift estimate and 1RM eccentrically loaded deadlift actual was r = 0.84 (p ≤ 0.01); a dependent t-test indicated the 1RM eccentrically loaded deadlift estimate was nearly significantly less than the 1RM eccentrically loaded deadlift actual (p = 0.061). Results suggest that conventional and eccentrically loaded deadlifts may be interchangeable within a training program; this may elicit the benefits of using a broader variety of ground-based multijoint compound movements in an athlete's strength and power training. Additionally, because of differences between predicted and actual 1RM scores in the deadlift, strength coaches should prioritize actual 1RM testing of their athletes to optimize deadlift training loads across the RM continuum.

Accuracy of Physical Self-Description Among Chronic Exercisers and Non-Exercisers.

This study addressed the role of chronic exercise to enhance physical self-description as measured by self-estimated percent body fat. Accuracy of physical self-description was determined in normal-weight, regularly exercising and non-exercising males with similar body mass index (BMI)'s and females with similar BMI's (n=42 males and 45 females of which 23 males and 23 females met criteria to be considered chronic exercisers). Statistical analyses were conducted to determine the degree of agreement between self-estimated percent body fat and actual laboratory measurements (hydrostatic weighing). Three statistical techniques were employed: Pearson correlation coefficients, Bland and Altman plots, and regression analysis. Agreement between measured and self-estimated percent body fat was superior for males and females who exercised chronically, compared to non-exercisers. The clinical implications are as follows. Satisfaction with one's body can be influenced by several factors, including self-perceived body composition. Dissatisfaction can contribute to maladaptive and destructive weight management behaviors. The present study suggests that regular exercise provides a basis for more positive weight management behaviors by enhancing the accuracy of self-assessed body composition.

The seated medicine ball throw as a test of upper body power in older adults.

Practitioners training the older adult may benefit from a low-cost, easy-to-administer field test of upper body power. This study evaluated validity and reliability of the seated medicine ball throw (SMBT) in older adults. Subjects (n = 33; age 72.4 ± 5.2 years) completed 6 trials of an SMBT in each of 2 testing days and 2 ball masses (1.5 and 3.0 kg). Subjects also completed 6 trials of an explosive push-up (EPU) on a force plate over 2 testing days. Validity was assessed via a Pearson Product-Moment correlation (PPM) between SMBT and EPU maximal vertical force. Reliability of the SMBT was determined using PPMs (r), Intraclass correlation (ICC, R) and Bland-Altman plots (BAPs). For validity, the association between the SMBT and the EPU revealed a PPM of r = 0.641 and r = 0.614 for the 1.5- and 3.0-kg medicine balls, respectively. Test-retest reliability of the 1.5- and 3.0-kg SMBT was r = 0.967 and r = 0.958, respectively. The ICC values of the 1.5- and 3.0-kg SMBT were R = 0.994 and 0.989, respectively. The BAPs revealed 94% of the differences between day 1 and 2 scores were within the 95% confidence interval of the mean difference. Test-retest reliability for the EPU was r = 0.944, R = 0.969. The BAPs showed 94% of the differences between day 1 and 2 scores were within the 95% confidence interval of the mean difference, for both medicine ball throws. In conclusion, for the older adult, the SMBT appears to be highly reliable test of upper body power. Its validity relative to the maximal force exerted during the EPU is modest. The SMBT is an inexpensive, safe, and repeatable measure of upper body power for the older adult.

Effect of functional isometric squats on vertical jump in trained and untrained men.

Functional isometrics (FIs) combine dynamic and isometric muscle actions and may hyperstimulate the nervous system leading to an enhanced postactivation potentiation (PAP) and improved subsequent performance. The purpose of this study was to investigate the impact of an FI squat on the countermovement vertical jump (CMVJ) in resistance trained and untrained men. Thirteen trained men (age: 22.8 +/- 3.2 years, mass: 90.0 +/- 16.3 kg, and height: 178.9 +/- 7.1 cm) and 8 untrained men (age: 28.5 +/- 5.9 years, mass: 101.5 +/- 23.0 kg, and height: 177.0 +/- 4.8 cm) participated. On separate days, subjects performed CMVJs after 2 different warm-up conditions. The warm-up conditions consisted of either 5 minutes of low-intensity cycling or 5 minutes of low-intensity cycling plus a 3-second FI squat with 150% of their 1 repetition maximum (1RM). A 2 x 3 repeated-measures analysis of variance with Bonferroni post hoc revealed that when comparing the 2 warm-up conditions in the trained subjects, a significant increase (p < 0.05) in CMVJ occurred at 4 minutes (2.4 cm, +5.1%) post-FI squat. This increase was maintained when subjects were retested at 5 minutes post (2.6 cm, + 5.5%). No significant difference in CMVJ was detected in the untrained group (p = 0.49). Results support the addition of an FI squat performed at 150% of 1RM to a low-intensity cycling warm-up to enhance PAP in resistance trained but not in untrained men as measured by CMVJ. Practically, adding functional isometrics to a warm-up scheme may significantly enhance acute, short-term power output in resistance trained men.

Physiological and psychophysical comparison between a lifting task with identical weight but different coupling factors.

The objective of the revised NIOSH (National Institute for Occupational Safety and Health) lifting equation is to prevent or reduce lifting-related injuries. The coupling component of the equation relates to quality of the grip (i.e., hand-to-object interface) and can be rated good, fair, or poor. Good coupling is theorized to reduce lifting stress, whereas poor coupling is theorized to increase lifting stress. This study compared the physiological and psychophysical stress between a lifting task with identical weight but different coupling factors. Subjects (n = 21; 26 +/- 6 years; 177.8 +/- 7.8 cm; 73.9 +/- 10.7 kg) transferred a milk crate or bag of dog food each weighing 12.5 kg back and forth from the floor to a table for 2, paced, 5-minute work bouts. Steady-state metabolic data were used to compare the lifting tasks. Results showed significantly higher oxygen consumption, caloric cost, heart rate, and rating of perceived exertion during the lifting task using the milk crate vs. the bag of dog food (p < 0.05). No difference in respiratory exchange ratio was observed (p > 0.05). In conclusion, a significantly higher metabolic cost and perceived exertion was observed when subjects performed a paced two-handed lifting task with good coupling factors than when using an object with poor coupling factors. When lifting stress is measured by metabolic cost and perceived exertion, these results are in contrast to expectations that a poor quality grip (i.e., poor coupling) would increase stress of a lifting task. Results of this study may help the work-place practitioner make decisions related to the use of the revised NIOSH lifting equation in the design and pacing of lifting-related tasks. Improved decision making may benefit productivity and enhance injury prevention in the workplace.

Anabolic androgenic steroids: use and perceived use in nonathlete college students.

OBJECTIVE: The authors investigated the use and perceived use of anabolic androgenic steroids (AAS) among nonathlete college students. PARTICIPANTS: The authors surveyed a sample of 485 nonathlete college students at a major metropolitan university. METHODS: They administered a survey on use and perceived use of AAS to the students. RESULTS: Forty-two participants (9%) reported using AAS (37 men, 5 women). Seniors were the most likely to use AAS (36%), and freshman the least likely (7%). Thirty-four percent of nonusers and 41% of users indicated they knew between 1 and 5 AAS users. Of the total sample, 36% perceived that 5% to 10% of nonathlete college students used AAS. Reasons for AAS use were because friends were using (7%), a desire to enhance physical appearance (45%), and a desire to increase physical performance (48%). CONCLUSIONS: These findings may have significant implications in planning strategic preventive educational programs, and health educators should target incoming college freshmen with the intent of dissuading AAS use.

Detraining in the older adult: effects of prior training intensity on strength retention.

In this study, we assessed the influence of training intensity on strength retention and loss incurred during detraining in older adults. In a previous study, untrained seniors (age = 71.0 +/- 5.0; n = 61) were randomly divided into 3 exercise groups and 1 control group. Exercise groups trained 2 days per week for 18 weeks with equivalent volumes and acute program variables but intensities of 2 x 15 repetitions maximum (RM), 3 x 9RM, or 4 x 6RM. Thirty of the original training subjects (age 71.5 +/- 5.2 years) participated in a 20-week detraining period. A 1RM for 8 exercises was obtained pre- and posttraining and at 6 and 20 weeks of detraining. The total of 1RM for the 8 exercises served as the dependent variable. Analysis of variance procedures demonstrated significant increases in strength with training (44-51%; p < 0.05), but no group effect. All training groups demonstrated significant strength decreases at both 6 and 20 weeks of detraining independent of prior training intensity (all group average 4.5% at 6 weeks and 13.5% at 20 weeks; p < 0.04). However, total-body strength was significantly greater than pretraining values after the detraining period (all group average 82% at 6 weeks and 49% at 20 weeks; p < 0.001). The results suggest that when older adults participate in progressive resistance exercise for 18 weeks, then stop resistance training (i.e., detrain), strength losses occur at both 6 and 20 weeks of detraining independent of prior resistance training intensity. However, despite the strength losses, significant levels of strength are retained even after 20 weeks of detraining. The results have important implications for resistance-trained older adults who could undergo planned or unplanned training interruptions of up to 5 months.

Metabolic demands of "junkyard" training: pushing and pulling a motor vehicle.

Junkyard training involves heavy, cumbersome implements and nontraditional movement patterns for unique training of athletes. This study assessed the metabolic demands of pushing and pulling a 1,960-kg motor vehicle (MV) 400 m in an all-out maximal effort. Six male, strength-trained athletes (29 +/- 5 years; 89 +/- 12 kg) completed 3 sessions. Sessions 1 and 2 were randomly assigned and entailed either pushing or pulling the MV. Oxygen consumption (VO(2)) and heart rate (HR) were measured continuously. Blood lactate was sampled immediately prior to and 5 minutes after sessions 1 and 2. Vertical jump was assessed immediately prior to and after sessions 1 and 2. During session 3 a treadmill VO(2)max test was conducted. No significant differences (p < 0.05) in VO(2), HR, or blood lactate occurred between pushing and pulling efforts. VO(2) and HR peaked in the first 100 m, and from 100 m on, VO(2) and HR averaged 65% and 96% of treadmill maximum values (VO(2)max = 50.3 ml x kg(-1) x min(-1); HRmax = 194 b x min(-1)). Blood lactate response from the push and pull averaged 15.6 mmol.L(-1), representing 131% of the maximal treadmill running value. Vertical jump decreased significantly pre to post in both conditions (mean = -10.1 cm, 17%). All subjects experienced dizziness and nausea. In conclusion, a 400-m MV push or pull is an exhausting training technique that requires a very high anaerobic energy output and should be considered an advanced form of training. Strength coaches must be aware of the ultra-high metabolic and neuromuscular stresses that can be imposed by this type of training and take these factors into consideration when plotting individualized training and recovery strategies.

Cold exposure and exercise metabolism.

Research regarding the effect of cold exposure on metabolism and substrate utilisation during exercise has produced inconsistent results. Intensity of exercise and training status of subjects are known to impact metabolism and substrate utilisation regardless of environmental conditions. Duration and intensity of cold exposure during exercise also may exert impact. Thus, systematic manipulation of these variables (fitness, intensity of exercise, cold conditions) should provide a means to determine metabolic and substrate utilisation patterns when exercising in the cold. However, a number of variables have been introduced into research methodologies that may confound results. Duration and intensity of cold exposure prior to exercise, and acclimation and clothing status of subjects may confound or override the influence of other variables. Future research addressing the impact of cold exposure on metabolism and substrate utilisation during exercise must attempt to isolate and control each influential factor (prior to and during exercise), and must be alert to the interactive effects that can occur.

Effects of a knee ligament injury prevention exercise program on impact forces in women.

Previous research suggests high impact forces generated during landings contribute to noncontact anterior cruciate ligament (ACL) injuries. In women, neuromuscular differences appear to modify the ability to dissipate landing forces when compared to men. This study examined peak vertical impact forces (F(p)) and rate of force development (RFD) following a 9-week, low-intensity (simple jump-landing-jump tasks) and volume (number of foot contacts per workout) plyometric-based knee ligament injury prevention (KLIP) program. Female subjects were randomly assigned into control (n = 14) and treatment (n = 14) groups. Treatment subjects attended KLIP sessions twice a week for 9 weeks, and control subjects received no intervention. Ground reaction forces (F(p) and RFD) generated during a step-land protocol were assessed at study onset and termination. Significant reductions in F(p) (p = 0.0004) and RFD (p = 0.0205) were observed in the treatment group. Our results indicate that 9 weeks of KLIP training altered landing strategies in women to lower F(p) and RFD. These changes are considered conducive to a reduced risk of knee injury while landing.

The effect of resistance-training intensity on strength-gain response in the older adult.

UNLABELLED: This study examined how training intensity affects strength gains in older adults over an 18-week training period using nonperiodized, progressive resistance-training protocols. Untrained men and women participants were separated into 4 groups: group A (n = 17, 71.4 +/- 4.6 years) performed 2 sets of 15 repetitions maximum (RM), group B (n = 13, 71.5 +/- 5.2 years) performed 3 sets of 9 RM, group C (n = 17, 69.4 +/- 4.4 years) performed 4 sets of 6 RM, group D (n = 14, 72.3 +/- 5.9 years) served as controls. Training groups exercised 2 days/week performing 8 resistance exercises. Except for training intensity, the acute program variables were equated between groups. A 1RM for 8 exercises was obtained every 6 weeks. The total of 1RM for the 8 exercises served as the dependent variable. RESULTS: repeated measures analysis of variance (ANOVA) and Scheffe post hoc revealed that, at 6 weeks, only groups B and C were significantly stronger than group D (p < 0.01). By weeks 12 and 18, all training groups were significantly stronger than controls (p < 0.01). However, no difference existed between groups A, B, and C at any time. The data suggests that, for protocols with equated acute program variables, strength gain is similar over 18 weeks for training intensities ranging from 6 to 15 RM in previously untrained older adults. When programming nonperiodized, progressive resistance exercise for novice senior lifters, in the initial phases of the program, a wide range of intensities may be employed with similar strength gain.

Anabolic steroid usage in athletics: facts, fiction, and public relations.

Anecdotal evidence suggests the widespread usage of anabolic steroids among athletes (20-90%), particularly at the professional and elite amateur levels. In contrast, scientific studies indicate that usage is rare and no higher than 6%. Conclusions from scientific studies suggest that anabolic steroid usage declines progressively from high school to college and beyond; however, anecdotal evidence claims the opposite trend. In this clash between "hard" scientific data vs. "soft" anecdotal information, it is natural that professionals would gravitate toward scientifically based conclusions. However, in the case of anabolic steroids (a stigmatized and illegal substance), should word-of-mouth testimony from individuals closest to the issues--those who have participated in and coached sports, those who have served as drug-testing overseers, and journalists who relentlessly track leads and verify sources--be set aside as irrelevant? Not if a complete picture is to emerge. In this review, hard scientific evidence is placed on the table side-by-side with soft anecdotal evidence, without weighting or bias. The purpose is to allow the opportunity for each to illuminate the other and, in so doing, potentially bring us a step closer to determining the true extent of anabolic steroid usage in athletics.

Talking to patients about aerobic exercise for disease prevention: an educational exercise for medical students.

Numerous data demonstrate the importance of physical activity in reducing obesity and cardiovascular mortality and morbidity. Research demonstrates the beneficial impact of physician counseling on health promoting behaviors. Unfortunately, few physicians or medical students receive formal training in exercise counseling. We describe an educational activity used to provide medical students with the tools needed to begin to engage patients in activity counseling.