Glenn A. Wright

Perception of fatigue during simulated competition

BACKGROUND Previous studies suggest that the rating of perceived exertion (RPE) increases during steady-state, open-loop exercise in proportion to the relative time to fatigue. This suggests that RPE is scalar and integrates physiological status and homeostatic disturbances. PURPOSE This study assessed the relationship between the rate of change in RPE, and relative distance in time trials at distances of 2.5, 5, and 10 km. It also assessed the rate of change in RPE during 5-km time trials while breathing hypoxic air. METHODS The subjects were well-conditioned cyclists. In part 1, each subject completed habituation time trials, and then randomly ordered time trials at each distance. The category ratio RPE was measured in 10% increments throughout each trial. In part 2, each subject completed three 5-km time trials while breathing different inspired gas mixtures (FiO2 = 0.2093 throughout the trial, FiO2 = 0.15 between 2 and 4 km, and FiO2 = 0.15 between 2.5 and 4 km). RPE was measured at 10% increments. RESULTS In part 1, when RPE was plotted against relative distance, there was no significant difference in the growth of RPE at proportional distances. In part 2, the decrease in power output during the hypoxic segments was sufficient that the growth of RPE was the same at each proportional distance. In both parts of the study, an RPE of 5 (hard) was achieved after 20% of the time trial distance, and an RPE of 8 was achieved after 80% distance. CONCLUSIONS This study supports the hypothesis that RPE increases similarly in relation to relative distance, regardless of the distance performed, and it suggests that the perception of effort has scalar properties.

Pattern of developing the performance template

Background: The pattern of energy expenditure during sustained high-intensity exercise is influenced by several variables. Data from athletic populations suggest that a pre-exercise conceptual model, or template, is a central variable relative to controlling energy expenditure. Aims: The aim of this study was to make systematic observations regarding how the performance template develops in fit individuals who have limited specific experience with sustained high-intensity exercise (eg, time trials). Methods: The study was conducted in four parts and involved measuring performance (time and power output) during: (A) six 3 km cycle time trials, (B) three 2 km rowing time trials, (C) four 2 km rowing time trials with a training period between trials 2 and 3, and (D) three 10 km cycle time trials. All time trials were self-paced with feedback to the subjects regarding previous performances and momentary pace. Results: In all four series of time trials there was a progressive pattern of improved performance averaging 6% over the first three trials and 10% over six trials. In all studies improvement was associated with increased power output during the early and middle portions of the time trial and a progressively greater terminal rating of perceived exertion. Despite the change in the pattern of energy expenditure, the subjects did not achieve the pattern usually displayed by athletes during comparable events. Conclusions: This study concludes that the pattern of learning the performance template is primarily related to increased confidence that the trial can be completed without unreasonable levels of exertion or injury, but that the process takes more than six trials to be complete.

The effect of beta-alanine supplementation on power performance during repeated sprint activity.

Sweeney, KM, Wright, GA, Brice, AG, and Doberstein, ST. The effect of β-alanine supplementation on power performance during repeated sprint activity. J Strength Cond Res 24(1): 79-87, 2010-The dipeptide carnosine has been shown to contribute to the buffer capacity of hydrogen ions (H+) during intense exercise. Increasing skeletal muscle carnosine levels through β-alanine (BA) supplementation has been shown to maintain acid-base balance, delay fatigue, and improve exercise performance. We designed this study to examine the effect of 5 weeks of BA supplementation on repeat high-intensity sprint performance. Nineteen, physically active, college men were divided into 2 groups (control [C], n = 10 or BA, n = 9). We performed double-blind placebo-controlled study where subjects ingested 4 g per day during the first week and 6 g per day over the next 4 weeks of a placebo (rice flour) or a BA supplement. Subjects completed 2 sets of 5 5-second sprints with 45-second recovery separated by 2 minutes of active recovery. All tests were conducted on a non-motorized treadmill against a resistance of 15% of the participants body weight. We recorded horizontal power (HP) of the running sprint. Post-exercise capillary blood samples were analyzed for lactate to determine the metabolic demands. There were no significant between-group differences (p > 0.05) in HPpeak or HPmean for the repeat sprint protocol. No significant between-group differences were found for performance decrement (% fatigue) for HPpeak or HPmean. In addition, no significant interactions were observed. Post-exercise blood lactate values were similar pre and post supplementation in both groups. The results of this study clearly indicate that 5 weeks of BA supplementation provides no benefit for repeat sprint performance.

Hip-Abductor Fatigue and Single-Leg Landing Mechanics in Women Athletes

CONTEXT Reduced hip-abductor strength and muscle activation may be associated with altered lower extremity mechanics, which are thought to increase the risk for anterior cruciate ligament injury. However, experimental evidence supporting this relationship is limited. OBJECTIVE To examine the changes in single-leg landing mechanics and gluteus medius recruitment that occur after a hip-abductor fatigue protocol. DESIGN Descriptive laboratory study. PATIENTS OR OTHER PARTICIPANTS Twenty physically active women (age  =  21.0 ± 1.3 years). INTERVENTION(S) Participants were tested before (prefatigue) and after (postfatigue) a hip-abductor fatigue protocol consisting of repetitive side-lying hip abduction. MAIN OUTCOME MEASURE(S) Outcome measures included sagittal-plane and frontal-plane hip and knee kinematics at initial contact and at 60 milliseconds after initial contact during 5 single-leg landings from a height of 40 cm. Peak hip and knee sagittal-plane and frontal-plane joint moments during this time interval were also analyzed. Measures of gluteus medius activation, including latency, peak amplitude, and integrated signal, were recorded. RESULTS A small (<1°) increase in hip-abduction angle at initial contact and a small (<1°) decrease in knee-abduction (valgus) angle at 60 milliseconds after contact were observed in the postfatigue landing condition. No other kinematic changes were noted for the knee or hip at initial contact or at 60 milliseconds after initial contact. Peak external knee-adduction moment decreased 27% and peak hip adduction moment decreased 24% during the postfatigue landing condition. Gluteus medius activation was delayed after the protocol, but no difference in peak or integrated signal was seen during the landing trials. CONCLUSIONS Changes observed during single-leg landings after hip-abductor fatigue were not generally considered unfavorable to the integrity of the anterior cruciate ligament. Further work may be justified to study the role of hip-abductor activation in protecting the knee during landing.

Kinetic Comparison of the Power Development Between Power Clean Variations

Abstract Suchomel, TJ, Wright, GA, Kernozek, TW, and Kline, DE. Kinetic comparison of the power development between power clean variations. J Strength Cond Res 28(2): 350–360, 2014—The purpose of this study was to compare the power production of the hang clean (HC), jump shrug (JS), and high pull (HP) when performed at different relative loads. Seventeen men with previous HC training experience, performed 3 repetitions each of the HC, JS, and HP at relative loads of 30, 45, 65, and 80% of their 1 repetition maximum (1RM) HC on a force platform over 3 different testing sessions. Peak power output (PPO), peak force (PF), and peak velocity (PV) of the lifter plus bar system during each repetition were compared. The JS produced a greater PPO, PF, and PV than both the HC (p < 0.001) and HP (p < 0.001). The HP also produced a greater PPO (p < 0.01) and PV (p < 0.001) than the HC. Peak power output, PF, and PV occurred at 45, 65, and 30% 1RM, respectively. Peak power output at 45% 1RM was greater than PPO at 65% (p = 0.043) and 80% 1RM (p = 0.004). Peak force at 30% was less than PF at 45% (p = 0.006), 65% (p < 0.001), and 80% 1RM (p = 0.003). Peak velocity at 30 and 45% was greater than PV at 65% (p < 0.001) and 80% 1RM (p < 0.001). Peak velocity at 65% 1RM was also greater than PV at 80% 1RM (p < 0.001). When designing resistance training programs, practitioners should consider implementing the JS and HP. To optimize PPO, loads of approximately 30 and 45% 1RM HC are recommended for the JS and HP, respectively.

Quantification of vertical ground reaction forces of popular bilateral plyometric exercises.

Wallace, BJ, Kernozek, TW, White, JM, Kline, DE, Wright, GA, Peng, H-T, and Huang, C-F. Quantification of vertical ground reaction forces of popular bilateral plyometric exercises. J Strength Cond Res 24(1): 207-212, 2010-The purpose of this study was to quantify the vertical ground reaction forces (VGRFs) developed during the performance of popular bilateral plyometric movements. Fourteen power-oriented track and field men of collegiate and national level randomly performed 3 trials of 9 different bilateral plyometric exercises in a single testing session. Three depth drop (DD) and 3 depth jump (DJ) conditions from 30, 60, and 90 cm heights (DD30, DD60, and DD90 and DJ30, DJ60, and DJ90) were tested, in addition to vertical jump (VJ), standing long jump (SLJ), and 2 consecutive jump (2CJ) conditions. Peak impact VGRFs were normalized to body weight. Additionally, all conditions were compared against the VJ in an intensity index. The SLJ condition resulted in a significantly higher peak VGRF than the 2CJ condition (p ≤ 0.05). 90DD, 90DJ, 60DD, and SLJ had a significantly greater peak VGRF (5.39, 4.93, 4.30, and 4.22 times body weight, respectively) than the VJ condition (3.34 times body weight). The 30DJ condition had an insignificantly smaller peak VGRF (2.78 times body weight) when compared with the VJ. Practitioners may use these findings to more effectively progress athletes in these movements based on their intensities.

Physiologic responses during indoor cycling.

Battista, RA, Foster, C, Andrew, J, Wright, G, Lucia, A, and Porcari, JP. Physiologic responses during indoor cycling. J Strength Cond Res 22: 1236-1241, 2008-During the last decade, there has been active interest in indoor cycling (e.g., spinning) as a method of choreographed group exercise. Recent studies have suggested that exercise intensity during indoor cycling may be quite high and may transiently exceed &OV0312;o2max. This study sought to confirm these findings, as the apparent high intensity of indoor cycling has implications for both the efficacy and the risk of indoor cycling as an exercise method. Twenty healthy female students performed an incremental exercise test to define &OV0312;o2max and performed 2 videotaped indoor exercise classes lasting 45 minutes and 35 minutes. &OV0312;o2, heart rate (HR), and rating of perceived exertion (RPE) were measured during the indoor cycling classes, with &OV0312;o2 data integrated in 30-second intervals. The mean %&OV0312;o2max during the indoor cycling classes was modest (74 ± 14%&OV0312;o2max and 66 ± 14%&OV0312;o2max, respectively). However, 52% and 35% of the time during the 45- and 35-minute classes was spent at intensities greater than the ventilatory threshold (VT). The HR response indicated that 35% and 38% of the session time was above the HR associated with VT. In 10 of the 40 exercise sessions, there were segments in which the momentary &OV0312;o2 exceeded &OV0312;o2max observed during incremental testing, and the cumulative time with exercise intensity greater than &OV0312;o2max ranged from 0.5 to 14.0 minutes. It can be concluded that although the intensity of indoor cycling in healthy, physically active women is moderate, there are frequent observations of transient values of &OV0312;o2 exceeding &OV0312;o2max, and a substantial portion of the exercise bouts at intensities greater than VT. As such, the data suggest that indoor cycling must be considered a high-intensity exercise mode of exercise training, which has implications for both efficacy and risk.

Translation of Submaximal Exercise Test Responses to Exercise Prescription Using the Talk Test.

Foster, C, Porcari, JP, Gibson, M, Wright, G, Greany, J, Talati, N, and Recalde, P. Translation of submaximal exercise test responses to exercise prescription using the talk test. J Strength Cond Res 23(9): 2425-2429, 2009-The exercise intensity at the Talk Test (TT) has been shown to be highly correlated with objective physiological markers, a useful outcome marker in patients with heart disease, a useful tool for avoiding exertional ischemia, and responsive to both positive and negative changes in exercise capacity. This randomized observational study evaluated the ability of the intensity at the TT during exercise testing to define absolute training workloads. Sedentary adults (n = 14) performed an incremental Balke type exercise test (3.0-3.5 mph at 0% grade, +2% grade every 2 minutes). Heart rate (HR), rating of perceived exertion (RPE), and TT were evaluated at each stage. Subsequently, the subjects performed 3 × 20-minute exercise bouts with the workload over the last 10 minutes of each bout equal to the absolute intensity at the stage preceding the LP (LP-1), at the last positive stage of the TT (LP), and at the first equivocal stage of the TT (EQ). During LP-1, LP, and EQ, HR was 140 ± 23, 151 ± 20, and 160 ± 21 bpm, or 73 ± 11, 79 ± 9, and 82 ± 9 % HRmax; RPE (CR scale) was 3.6 ± 1.5, 4.4 ± 1.8, and 6.3 ± 2.2. The TT Score-ranked as 1 = comfortable speech, 2 = slightly uncomfortable speech, and 3 = speech not comfortable-was 1.4 ± 0.5, 1.8 ± 0.4, and 2.6 ± 0.5 LP-1, LP, and at EQ, LP, respectively. The results suggest that to prescribe absolute training intensity from the TT and to get appropriate HR, RPE, and TT responses in sedentary individuals during training, the workload needs to be based on the intensity approximately 1 stage (∼1.0-1.2 metabolic equivalents) below the LP stage observed during an incremental test.

A comparison between back squat exercise and vertical jump kinematics: implications for determining anterior cruciate ligament injury risk.

Wallace, BJ, Kernozek, TW, Mikat, RP, Wright, GA, Simons, SZ, and Wallace, KL. A comparison between back squat exercise and vertical jump kinematics: implications for determining anterior cruciate ligament injury risk. J Strength Cond Res 22: 1249-1258, 2008-Women are up to eight times more likely than men to suffer an anterior cruciate ligament (ACL) injury, and knee valgus is perhaps the most at-risk motion. Women have been shown to have more knee valgus than men in squatting movements and while landing. The purposes were to investigate whether a relationship exists between lower-extremity frontal plane motions in squatting and landing, whether gender differences exist, and whether squat or hip abduction strength relates to knee valgus while landing. Eleven collegiate Division III soccer players and 11 recreationally trained men were tested for maximal vertical jump height and for squat and hip abduction strength. On the second day of testing, subjects performed light (50% one repetition maximum) and heavy (85%) squat protocols and three landings from their maximal vertical jump height. Pearsons product-moment correlation coefficients and a 2 × 10 factorial analysis of variance with t-test post hoc comparisons (p ≤ 0.05) were conducted. No strong correlations were shown between any of the squat conditions (eccentric and concentric light, eccentric and concentric heavy) and landing for hip abduction or knee valgus angles. Squat strength did not correlate well with knee valgus angle during landing in men or women. However, hip abduction strength did in women (R2 = 0.51) but not men (R2 = 0.10). In hip abduction angle, the eccentric portion of the light squat, eccentric and concentric portions of the heavy squat, and vertical jump landing conditions were different between genders. In knee valgus angle, only the heavy squat conditions were significantly different. Squat strength and observing squat kinematics do not seem to be a method of identifying those at risk while landing; however, hip abduction strength may be in women.

Effects of acute static stretching of the throwing shoulder on pitching performance of national collegiate athletic association division III baseball players.

Haag, SJ, Wright, GA, Gillette, CM, and Greany, JF. Effects of acute static stretching of the throwing shoulder on pitching performance of National Collegiate Athletic Association Division III baseball players. J Strength Cond Res 24(2): 452-457, 2010-Stretching is a common component of an athletic warm-up even though many studies have demonstrated that pre-event static stretching can decrease strength and power performance. The purpose of this study was to examine the effects of acute static stretching of the throwing shoulder on pitching velocity and accuracy of National Collegiate Athletic Association Division III baseball players. Twelve collegiate baseball players, including 6 pitchers and 6 position players, participated in the study. Each participant completed 2 separate testing protocols over a span of 4-6 days. In the experimental condition (SS), 6 static stretches were applied to the throwing shoulder after an active warm-up. After a rest period of 5-10 minutes, participants were allowed 5 warm-up pitches from a pitching mound. Participants then threw 10 pitches measured for velocity and accuracy. The control condition (NS) followed the same procedure but did not include the 6 static stretches. Testing was conducted in an indoor practice facility during normal team practice. No significant differences were found in average velocity, maximum velocity, or accuracy measures when comparing the SS and NS conditions. These results suggest that acute static stretching of the throwing shoulder does not have a significant impact on baseball pitching performance. Static stretching of the shoulder may be performed during a warm-up before a throwing activity.