Jeffrey A. Potteiger

Muscle damage and resting metabolic rate after acute resistance exercise with an eccentric overload.

PURPOSE The purpose of this investigation was to determine whether muscle damage caused from acute resistance exercise with an eccentric overload would influence resting metabolic rate (RMR) up to 72 h postexercise in resistance-trained (RT) and untrained (UT) subjects. METHODS Nine RT and 9 UT male subjects (mean +/- SD; age = 20.7 +/- 2.1 yr; body mass = 79.0 +/- 1.4 kg; height = 178.4 +/- 3.1 cm; and body fat = 10.2 +/- 1.6%) were measured for RMR, creatine kinase concentration ([CK]), and rating of perceived muscle soreness (RPMS) on five consecutive mornings. To induce muscle damage, after the measurements on day 2, each subject performed leg presses that emphasized the eccentric movement for 8 sets at his six-repetition maximum (6-RM). RESULTS Compared with baseline, the RMR (kJ x d(-1) and kJ x kg FFM(-1) x h(-1) was significantly elevated for RT and UT at 24 h and 48 h postexercise. From 24 h to 48 h to 72 h postexercise, RMR significantly decreased within both groups. The UT group had a significantly higher RMR at 24 h (9,705.4 +/- 204.5 kJ x d(-1)) and 48 h postexercise (8,930.9 +/- 104.4 kJ x d(-1)) when compared with the RT group (9,209.3 +/- 535.3 and 8,601.7 + 353.7 kJ x d(-1)). Both [CK] and RPMS showed a similar time course. CONCLUSION There was a significantly higher [CK] for the UT group at 24 h postexercise (320.4 +/- 20.1 U x L(-1)) and for both [CK] and RPMS at 48 h (1,140.3 +/- 37.1 U x L(-1) and 4.4 +/- 0.5, respectively) and 72 h postexercise (675.9 +/- 41.7 U x L(-1) and 1.67 +/- 0.5, respectively) when compared with the RT group (24 h, 201.9 +/- 13.4 U x L(-1); 48 h, 845.4 +/- 30.7 U x L(-1) and 3.7 +/- 0.5: and 72 h postexercise, 420.2 +/- 70.2 U x L(-1) and 0.89 +/- 0.3). These data indicate that eccentrically induced muscle damage causes perturbations in RMR up to 48 h postexercise.

INFLUENCE OF MUSIC ON RATINGS OF PERCEIVED EXERTION DURING 20 MINUTES OF MODERATE INTENSITY EXERCISE

The effects of different types of music on ratings of perceived exertion (RPE) during 20 min. of moderate intensity exercise were examined. 27 physically active subjects (age 18–30 yr.) performed a graded exercise test on a cycle ergometer to establish peak aerobic power (VO2peak). Four 20-min. exercise sessions were performed at a power output equal to 70% of VO2peak in a soundproof visually sterile room. The sessions were randomly assigned from the conditions of fast upbeat music, classical music, self-selected music, and no music. Heart rate, peripheral RPE, central RPE, and overall RPE were measured every 5 min. during exercise. No significant differences were found in heart rate among the four conditions indicating similar exercise intensity during each condition. Each type of music resulted in a reduced peripheral, central, and overall RPE when compared with the no-music condition. The data indicate that different types of music can act as an effective passive distractor during exercise and are associated with lower ratings of perceived exertion.

Relationship Between Body Composition, Leg Strength, Anaerobic Power, and On-Ice Skating Performance in Division I Men's Hockey Athletes

Potteiger, JA, Smith, DL, Maier, ML, and Foster, TS. Relationship between body composition, leg strength, anaerobic power, and on-ice skating performance in division I mens hockey athletes. J Strength Cond Res 24(7): 1755-1762, 2010-The purpose of this study was to examine relationships between laboratory tests and on-ice skating performance in division I mens hockey athletes. Twenty-one men (age 20.7 ± 1.6 years) were assessed for body composition, isokinetic force production in the quadriceps and hamstring muscles, and anaerobic muscle power via the Wingate 30-second cycle ergometer test. Air displacement plethysmography was used to determine % body fat (%FAT), fat-free mass (FFM), and fat mass. Peak torque and total work during 10 maximal effort repetitions at 120°·s−1 were measured during concentric muscle actions using an isokinetic dynamometer. Muscle power was measured using a Monark cycle ergometer with resistance set at 7.5% of body mass. On-ice skating performance was measured during 6 timed 89-m sprints with subjects wearing full hockey equipment. First length skate (FLS) was 54 m, and total length skate (TLS) was 89 m with fastest and average skating times used in the analysis. Correlation coefficients were used to determine relationships between laboratory testing and on-ice performance. Subjects had a body mass of 88.8 ± 7.8 kg and %FAT of 11.9 ± 4.6. First length skate-Average and TLS-Average skating times were moderately correlated to %FAT ([r = 0.53; p = 0.013] and [r = 0.57; p = 0.007]) such that a greater %FAT was related to slower skating speeds. First length skate-Fastest was correlated to Wingate percent fatigue index (r = −0.48; p = 0.027) and FLS-Average was correlated to Wingate peak power per kilogram body mass (r = −0.43; p = 0.05). Laboratory testing of select variables can predict skating performance in ice hockey athletes. This information can be used to develop targeted and effective strength and conditioning programs that will improve on-ice skating speed.

The effects of buffer ingestion on metabolic factors related to distance running performance

AbstractWe examined the effects of sodium bicarbonate (BIC) and sodium citrate (CIT) ingestion on distance running performance. Seven male runners [mean

Changes in Height, Body Weight, and Body Composition in American Football Players From 1942 to 2011

\dot VO_{2max}

Comparison of Passive Sensory Stimulations on RPE during Moderate Intensity Exercise

= 61.7 (SEM 1.7) ml · kg−1 · min−1] performed three 30-min treadmill runs at the lactate threshold (LT) each followed by a run to exhaustion at 110% of LT. The runs were double-blind and randomly assigned from BIC (0.3 g · kg body mass−1), CIT (0.5 g · kg body mass−1) and placebo (PLC, wheat flour, 0.5 g · kg body mass−1). Venous blood samples were collected at 5, 15 and 25 min during the run and immediately post-exhaustion (POST-EX) and analysed for pH, and the concentrations of lactate ([1a−]b) and bicarbonate ([HCO3− ]). Performance was measured as running time to exhaustion at 110% of LT (TIME-EX). The pH was significantly higher (P ≤ 0.05) for the BIC and CIT trials during exercise, but not POST-EX compared to PLC. The [1a−]b was significantly higher (P ≤ 0.05) for the CIT trial compared to PLC during exercise, and for both CIT and BIC compared to PLC at POST-EX. Blood [HCO3−] was significantly higher (P ≤ 0.05) during exercise for BIC compared to PLC. TIME-EX was not significantly different among treatments: BIC 287 (SEM 47.4) s; CIT 172.8 (SEM 29.7) s; and PLC 222.3 (SEM 39.7) s. Despite the fact that buffer ingestion produced favourable metabolic conditions during 30 min of high intensity steady-state exercise, a significant improvement in the subsequent maximal exercise run to exhaustion did not occur.

Glucose Uptake After Resistance Training of Different Intensities but of Equal Work Volume

ObjectiveTo examine the effects of creatine supplementation on anterior compartment pressure of the lower leg at rest and following exercise. Design14 college-age males received creatine or placebo supplementation for 34 days. At baseline, anterior compartment pressure was measured preexercise, immediately postexercise, and 1, 5, and 15 minutes postexercise after a level treadmill run for 20 minutes at 80% of maximal aerobic power. InterventionFollowing baseline testing, subjects began a 6-day creatine or placebo loading phase at a dosage of 0.3 g · kg body mass−1 · d−1. This was followed by a 28-day maintenance phase at a dosage of 0.03 g · kg body mass−1 · d−1. Subjects and investigators were blinded as to treatment administration. Subjects continued to exercise during the supplementation period. After 6 days and 34 days of supplementation, anterior compartment pressure was measured at rest and following exercise. ResultsCreatine supplementation for 6 days significantly increased compartment pressure compared with the placebo group at rest (76%), immediately post- (150%), 1 minute post- (125%), 5 minute post- (106%), and 15 minute postexercise (77%). Anterior compartment pressures continued to remain significantly higher for the creatine group compared with the placebo group at rest (72%), immediately post- (125%) and 1 minute postexercise (180%) after 34 days of creatine supplementation. ConclusionsThese data indicate that creatine supplementation abnormally increases anterior compartment pressure in the lower leg at rest and following 20 minutes of level running at 80% of maximal aerobic power.

Effects of different macronutrient consumption following a resistance-training session on fat and carbohydrate metabolism.

Abstract Anzell, AR, Potteiger, JA, Kraemer, WJ, and Otieno, S. Changes in height, body weight, and body composition in American football players from 1942 to 2011. J Strength Cond Res 27(2): 277–284, 2013—The purpose of this study was to document changes in height (cm), body weight (kg), and body composition (%fat) of American football players from 1942 to 2011. Published articles were identified from databases and cross-referencing of bibliographies. Studies selected met the requirements of (1) having 2 of 3 dependent (height, body weight, and body composition) variables reported in the results; (2) containing a skill level of college or professional; (3) providing measured not self-reported data; and (4) published studies in English language journals. The data were categorized into groups based on skill level (college and professional). The player positions were grouped into 3 categories: mixed linemen (offensive and defensive linemen, tight ends, and linebackers), mixed offensive backs (quarterback and running backs), and mixed skilled positions (defensive backs and wide receivers). Linear regression was used to provide slope estimates and 95% confidence intervals (CIs). Unpaired t-tests were used to determine whether an individual regression slope was significantly different from zero. Statistical significance was set at p < 0.017. College level players in all position groups have significantly increased body weight over time (95% CI: mixed lineman 0.338–0.900 kg·y−1; mixed offensive backs 0.089–0.298 kg·y−1; mixed skilled 0.078–0.334 kg·y−1). The college level mixed linemen showed a significant increase over time for height (95% CI: 0.034–0.188 cm·y−1) and body composition (0.046–0.275% fat per year). Significant increases in body weight over time were found for professional level mixed lineman (95% CI: 0.098–0.756 kg·y−1) and mixed offensive backs (95% CI: 0.1800–0.545 kg·y−1). There were no other significant changes at the professional level. These data demonstrate that body weight of all college players and professional mixed lineman have significantly increased from 1942 to 2011.