Submaximal Testing to Estimate Aerobic Capacity Using a Matrix C5x Stepmill.

The primary purpose of this study was to determine if the Matrix C5x stepmill's preprogrammed submaximal test is able to accurately predict maximal oxygen uptake. Sixteen participants completed a maximal treadmill test and a preprogrammed submaximal test on a Matrix C5x stepmill. Oxygen uptake was measured using a Cosmed K5 during both tests. Maximal oxygen uptake (VO2max) was calculated from submaximal data using a multi-stage calculation and compared against measured VO2max from the maximal test and estimated VO2max from the submaximal stepmill test. METs were also measured during the submaximal test and compared to the METs estimated by the stepmill and METs calculated using submaximal stepping equations. Measured VO2max (39.18 α 6.6 ml.kg-1.min-1) was significantly higher (p < 0.001) than estimated VO2max (28.06 α 3.2 ml.kg-1.min-1) and calculated VO2max (35.58 α 8.0 ml.kg-1.min-1). Measured METs were significantly (p = 0.04) higher than estimated METs in all stages, and higher than calculated METs in stage 1 of the submaximal test. The C5x did not provide accurate estimations of METs or maximal oxygen uptake. Calculating maximal oxygen uptake from submaximal stepmill data may provide an alternative, although development of a new equation may be warranted.

The effect of load based on body mass percentage on peak power output in the hang power clean, hang high pull, and mid-thigh clean pull.

BACKGROUND: Prescribing load at the peak power output (PPO) is one of the strategies utilized to enhance lower-body muscle power. PPO of an exercise is determined based on a relative percentage of the one-repetition maximum test (1RM). However, 1RM tests may be impractical in some weightlifting derivatives. This study aimed to identify the PPO of the hang power clean (HPC), hang high pull (HHP), and mid-thigh clean pull (MTCP) based on a relative percentage of body mass (BM). METHODS: Fifteen males with weightlifting experience performed HPC, HHP, and MTCP at loads ranging from 30-90% BM. Kinematic data were collected through a 16-camera infrared motion capture system and processed based on a three-dimensional lower-extremity model. Ground reaction force (GRF) data were collected from two force plates. PPO was calculated as the product of model center of mass velocity and combined vertical GRF during the concentric phase. RESULTS: PPO occurred at 90% BM for the HPC. In addition, the PPO occurred at 90% BM for the HHP and it was not different than 70% and 80% BM. At last, the PPO for MTCP occurred at 80% BM and it was not different than 60% and 70% BM. CONCLUSIONS: Relative percentages of BM can be used to determine PPO in the HPC, HHP, and MTCP. PPO during HPC is achieved at 90% BM, while the PPO for HHP and MTCP is achieved between 70% to 90% BM and 60 to 80% BM, respectively.

Low Muscular Strength, Weight Status, and Metabolic Syndrome in Adolescents: National Health and Nutrition Examination Survey 2011-2014.

PURPOSE: To investigate the association between muscular strength and metabolic syndrome (MetS), with a specific focus on the role of weight status, using a nationally representative sample of US youth. METHODS: The analysis included 409 boys and 415 girls from the 2011 to 2014 National Health and Nutrition Examination Survey between 12 and 18 years of age. The prevalence of MetS was defined using age- and sex-specific criteria for abdominal obesity, elevated triglycerides, blood pressure, fasting glucose, and low high-density lipoprotein (HDL) cholesterol. Strength was assessed via handgrip dynamometer and expressed as age- and sex-specific z scores of relative strength. Low strength was defined as a relative strength below the 25th percentile. Analyses controlled for age, sex, race/ethnicity, physical activity, and weight status. RESULTS: The sample prevalence of MetS was approximately 5.3%. However, MetS prevalence was 18.5% in overweight/obese youth with low strength. The adjusted odds of MetS were 3.1 (95% confidence interval, 1.5-6.3, P < .001) times higher for overweight/obese youth with low strength versus sufficient strength. CONCLUSION: Muscular strength is predictive of adolescent MetS, specifically in those with unhealthy weight status. Approximately one in 5 overweight/obese youth with low strength had MetS. These findings highlight the relevance of muscular strength in youth cardiometabolic morbidities.

Acute and Session Ratings of Perceived Exertion in a Physical Education Setting.

A commonly stated rationale for examining the use of ratings of perceived exertion with youth is its potential value as an assessment of intensity in physical education settings. The purpose of this study was to examine the relation between ratings of perceived exertion and heart rate in a natural physical education setting. Sixth through eighth grade students performed cardiovascular and muscle endurance circuits and then recorded ratings and heart rate. It was hypothesized that, similar to laboratory studies, strong positive correlations would be seen between heart rate and ratings of perceived exertion, which would provide additional support for the use of ratings of perceived exertion in physical education. However, only low to moderate correlations were found. When data collection occurs in a natural physical education setting, there are challenges that may result in poor correlational results between variables such as heart rate and perceived exertion that demonstrate strong relationships when examined in laboratory settings.

Safety of using the adult OMNI Resistance Exercise Scale to determine 1-RM in older men and women.

Older adults may be susceptible to injury during high-intensity resistance exercise. It has been suggested that it may be more protective to predict one-repetition maximum (1-RM) than to measure it because of the high intensity associated with 1-RM testing, but it may be necessary to measure 1-RM for functional, diagnostic, or clinical purposes. The method of using the OMNI Resistance Exercise Scale (OMNI-RES) was examined as a guide for hexagenarian adults in estimating 1-RM. 22 healthy men (M age = 64.3 yr., SD = 3.2) and 27 women (M age = 63.8 yr., SD = 2.8) volunteered. After two weeks of orientation, participants used a predetermined rating of perceived exertion to select resistance in the assessment of 1-RM and again after 12 weeks of training. At the 1-RM trials, participants were asked to report soreness or injury during or after the exercise sessions. There were no reported incidences of injury during the current investigation. The current results provide a practical method to estimate 1-RM in older adults. As such, the OMNI-RES can be used safely in a potentially at-risk population.

Selection of resistance exercise intensity using ratings of perceived exertion from the OMNI-RES.

This investigation evaluated the use of OMNI-Resistance Exercise Scale ratings of perceived exertion as a method for selecting training intensities that are appropriate for improving muscular fitness. 20 women (M = 21.3 yr., SD = 2.2) completed a one-repetition maximum for the chest press and knee extension. Participants returned for three sessions during which they were asked to select resistances which elicited the feelings of exertion associated with ratings of 3 (i.e., Easy to Somewhat easy), 6 (i.e., Somewhat hard) and 9 (i.e., Hard to Extremely hard). The average percentage of maximum lifted at a 3, 6, and 9 was 50, 69, and 88% for the chest press and 56, 74, and 90% for the knee extension, respectively. Effect sizes indicated large differences across the three ratings of perceived exertion within sessions and small differences between sessions. Intraclass correlation coefficients ranged from .69 to .95. The results indicated that OMNI-Resistance Exercise Scale ratings of 3, 6, and 9 can be used to accurately and reliably select intensities that are appropriate for improving muscular fitness.

Strength tracking using the OMNI resistance exercise scale in older men and women.

Strength tracking uses ratings of perceived exertion (RPE) as a reference value to determine changes in strength as a function of a resistance training program. The purpose of this investigation was to determine if the OMNI Resistance Exercise Scale (OMNI-RES) could be used to track training-induced strength changes in older adults. Twenty-two men (64.3 + 3.2 years) and 27 women (63.8 + 2.8 years) volunteered to participate. Subjects underwent a maximal lifting test, during which they estimated perceived exertion before and following 12 weeks of resistance exercise training. Leg press (LP), latissimus dorsi pull-down (LA), chest press (CP), leg extension (LE), leg curl (LC), arm extension (AE), and arm curl (AC) were performed. Paired samples t-tests were used to compare resistance lifted pre- and post-training at each criterion RPE (4, 6, and 8). One repetition maximum increased from pretraining to post-training (p < 0.05) for all exercises. The resistance lifted at each criterion RPE also increased (p < 0.05) during the 12-week training session for every exercise. Older adults lifted more weight at 3 criterion RPEs as their strength increased, providing an RPE-based procedure to track strength training changes using the OMNI-RES. As such, it seems that RPE from the OMNI-RES can be used to track strength in older adults.

Physiologic and metabolic responses to a continuous functional resistance exercise workout.

The purpose of this study was to evaluate the physiologic and perceptual responses to a continuous functional exercise workout. Ten men and 10 women (21.2 +/- 2.4 and 21.0 +/- 1.5 years) completed a maximal oxygen uptake test, strength test, and body composition analysis. Subjects then participated in 3 familiarization sessions, during which they followed a videotaped routine that consisted of a series of functional resistance exercises performed in a continuous manner. Subjects performed the same routine in a final session, during which VO2, VCO2, respiratory exchange ratio (RER), RPE, and heart rate were measured and blood samples were taken and analyzed for blood lactic acid concentration. Descriptive statistics were calculated for RPE, RER, blood lactic acid concentration, energy expenditure, and absolute and relative oxygen uptake and heart rate. Energy expenditure was calculated using VO2 and RER. Independent t-tests were used to examine differences between men and women for oxygen consumption, weight lifted, and energy expenditure during the workout. Subjects had a mean VO2 of 27.8 ml.kg.min (51% of VO2 peak and 47.8% of VO2 reserve), a mean heart rate of 156 bpm (83% of maximum heart rate), and a mean RER of 0.91. The mean RPE was 5.9, and the mean difference between pre and post lactic acid concentration was 2.5 mmol.L. The mean total caloric expenditure was 289 kcal. Men lifted significantly heavier weights and expended more total calories than women. Caloric expenditure (kcal x kg x min), VO2, and weight lifted were similar between men and women when expressed relatively. Performing dynamic functional exercises in a continuous manner resulted in energy expenditure values, but not relative VO2 values, that meet the American College of Sports Medicine recommendations.

RPE at relative intensities after 12 weeks of resistance-exercise training by older adults.

The constant-RPE tracking model monitors progress over the course of exercise training. During aerobic exercise, prior work using this model has demonstrated similar relative intensities pre- and posttraining, while the absolute workload increases posttraining. However, the prediction equation associated with these changes has not been examined during resistance training. 22 men and 27 women (M age 64 yr.) participated in a 12-wk. resistance training. Orientation determined resistances associated with RPEs of 4, 5-6, 7-8, and 9 on the OMNI-Resistance Exercise Scale for each of seven exercises for each participant. Individuals trained 3 days a week for 12 wk. Linear regression was used to calculate percent of 1-repetition maximum (%1-RM) at RPE 4, 6, and 8 for the exercises. Paired sample t tests, comparing pre- and posttraining %1-RMs at each RPE, indicated that posttraining %1-RMs were higher for RPE 4 and 6 for each exercise, while at RPE 8, results were significant for only 3 exercises. Thus for at least the RPE 4 and 6, the constant RPE tracking model is appropriate for resistance exercise; however, the equation of prediction appears to differ from that for aerobic exercise. Development of a new prediction equation may be necessary to track relative strength in older adults.

The validity of using prior ratings of perceive exertion to regulate resistance exercise intensity.

This investigation examined the validity of using ratings of perceived exertion (RPE) to regulate intensity during resistance exercise. 19 male (M age = 22.2 yr., SD = 2.7) and 19 female (M age = 21.4 yr., SD = 2.3) participants estimated exertion when performing the knee extension at 40% to 90% of one-repetition maximum. One week later, participants were asked to produce weights for the knee extension that elicited the feelings of exertion associated with 9, 13, and 17 on the Borg RPE scale. The weight produced at 9, 13, and 17 during the production session was compared to the weight lifted at each RPE during the estimation session. The effect sizes associated with the differences in weight lifted across sessions at each RPE were generally small in magnitude, especially at the higher intensities (ES = .40, -.09, .15, respectively). The results of this investigation support the use of RPE as a method of prescribing the intensity of resistance exercise.

Construct validity of the OMNI resistance exercise scale.

This study examined the construct validity of the Adult OMNI Perceived Exertion Scale for Resistance Exercise (OMNI-RES). Forty (20 men and 20 women) subjects performed 1 repetition of the knee extension exercise at 40, 50, 60, 70, 80, and 90% of the 1 repetition maximum. Active muscle and overall body ratings of perceived exertion (RPE) were collected from the Borg 15-category RPE scale and the OMNI-RES immediately following each repetition. Construct validity was established by correlating RPE from the OMNI-RES with RPE from the Borg RPE scale using regression analysis. The results indicated a positive and linear relationship between RPE from the OMNI-RES and RPE from the Borg scale for both men and women. Validity coefficients ranged from r = 0.94 to 0.97. The high level of construct validity indicates that the OMNI-RES measures the same properties of exertion as the Borg RPE scale during resistance exercise and suggests that the 2 scales can be used interchangeably during resistance exercise.

Anchoring procedures in reliability of ratings of perceived exertion during resistance exercise.

Although the validity of perceived exertion as a method of monitoring the intensity of resistance exercise has been established, little is known about the test-retest reliability of ratings of perceived exertion during resistance exercise. Specifically, it is unknown whether the use of different anchoring procedures influences the reliability of ratings of perceived exertion. 30 men were assigned to an Exercise, Memory, or combined Exercise and Memory anchoring group. Participants completed an assessment of maximal leg-extension strength and were introduced to the Borg 15-category rating of perceived exertion scale through anchoring procedures that varied across groups. During two sessions of resistance exercise, participants rated active muscle perceived exertion after performing one repetition of the leg-extension exercise at 40%, 50%, 60%, 70%, 80% and 90% of the one-repetition maximum. A three-factor (Group x Intensity x Session) analysis of variance was performed to examine the perceived exertion data. Perceived exertion increased significantly (p<.01) with increasing exercise intensity in all groups and in both sessions. Mean ratings did not differ significantly among groups. Reliability was assessed for each group. Intraclass correlation coefficients ranged from .07 to .80 and percent agreement ranged from 60% to 90%. The results indicate that the reliability of ratings of perceived exertion during resistance exercise is acceptable regardless of the type of anchoring procedures used.

Ratings of perceived exertion and muscle activity during the bench press exercise in recreational and novice lifters.

This study examined ratings of perceived exertion (RPE) and electromyography (EMG) during resistance exercise in recreational and novice lifters. Fourteen novice (age = 21.5 +/- 1.5 years) and 14 recreationally trained (age = 21.9 +/- 2.2 years) women volunteered to perform the bench press exercise at 60 and 80% of their 1 repetition maximum (1RM). RPE and EMG were measured during both intensities. Statistical analyses revealed that active muscle RPE increased as resistance exercise intensity increased from 60% 1RM to 80% 1RM (12.32 +/- 1.81 vs. 15.14 +/- 1.74). Integrated EMG also increased as resistance exercise intensity increased from 60% 1RM to 80% 1RM (in the pectoralis major; 98.62 +/- 17.54 vs. 127.98 +/- 29.02). No significant differences in RPE or EMG were found between novice and recreational lifters. These results indicate that RPE is related to the relative exercise intensity lifted as well as muscle activity during resistance exercise for both recreational and novice lifters. These results support the use of RPE as a method of resistance exercise intensity estimation for both types of lifters.

Self-regulated cycling using the Children's OMNI Scale of Perceived Exertion.

PURPOSE: An estimation and production paradigm was used to determine whether clinically normal 8- to 12-yr-old female (N = 18) and male (N = 18) children could (a) self-regulate intermittent cycle ergometer exercise using a prescribed target rating of perceived exertion (RPE), (b) discriminate between target RPEs, and (c) produce intermittent target RPEs in both an ascending and descending sequence. METHODS: Overall body RPE was assessed with the Children's OMNI Scale (0-10). Subjects underwent (a) one orientation trial, (b) one estimation (E) trial, and (c) two production (P) trials. During E, RPE was estimated each minute of a progressive cycle ergometer test. During the 3-min intermittent P trials, subjects titrated cycle brake force to produce either an RPE sequence of 2 and 6 (ascending) or 6 and 2 (descending). The P trials simulated short, intermittent exercise typical of children's play. RESULTS: Oxygen uptake (VO2) did not differ between E and P at a target RPE of 2 (0.63 versus 0.66 L x min(-1)) and 6 (1.27 vs 1.21 L x min(-1)). Heart rate (HR) did not differ between E and P at a target RPE of 2 (104.1 vs 102.6 beats.min-1) and 6 (153.7 vs 154.5 beats x min(-1)). Both VO2 and HR were higher (P < 0.01) at a target RPE-6 than -2. Responses were not affected by gender or production sequence. CONCLUSION: Young female and male children were able to use the OMNI Scale to self-regulate short-duration intermittent cycle exercise intensity.

Perceived exertion, electromyography, and blood lactate during acute bouts of resistance exercise.

PURPOSE: This study examined ratings of perceived exertion (RPE) during resistance exercise in women. In addition, changes in blood lactic acid and biceps muscle activity assessed using electromyography (EMG) were investigated as potential mediators of RPE during resistance exercise. METHODS: Twenty female volunteers (age, 25 +/- 4 yr) performed one set of biceps curl exercise at 30%, 60%, and 90% of their one-repetition maximum (1-RM). Total work was held constant by varying the number of repetitions during each of the three intensities. The three intensities were performed in random order. RPE responses were assessed for both the active muscle (RPE-AM) and the overall body (RPE-O) following each intensity. EMG data were collected from the biceps brachii muscle during each intensity. Blood samples were taken before and following the intensities and analyzed for blood lactic acid concentration. RESULTS: A two-factor repeated-measures ANOVA showed a significant RPE (region) x intensity interaction (P < 0.02). Both RPE-AM and RPE-O increased as the intensity of exercise increased. EMG activity increased significantly (P < 0.01) as the intensity of exercise increased. A two-factor repeated measures ANOVA performed on the blood lactate data showed a significant (P < 0.04) time x intensity interaction. Postexercise [Hla] was significantly greater (P < 0.01) at 90% 1-RM than at 30% 1-RM. No significant differences were found in [Hla] between 30% and 60% 1-RM, or between 60% and 90% 1-RM. CONCLUSION: These results indicate that monitoring RPE may be a useful technique for regulating resistance exercise intensity. Moreover, blood lactate and activity of the involved muscle may mediate the relation between RPE and resistance exercise intensity.

Ratings of perceived exertion in active muscle during high-intensity and low-intensity resistance exercise.

This investigation compared ratings of perceived exertion specific to the active muscles used during resistance exercise (RPE-AM) using the 15-category Borg scale during high-intensity (HIP) and low-intensity (LIP) weight lifting. Ten men (23.2 +/- 3.6 years) and 10 women (21.8 +/- 2.7 years) performed 2 trials consisting of seven exercises: bench press (BP), leg press, latissimus dorsi pull down, triceps press, biceps curl, shoulder press, and calf raise. The HIP and LIP protocols were completed in counterbalanced order. During HIP, subjects completed 5 repetitions using 90% of 1 repetition maximum (1RM). RPE-AM was measured after every repetition. During LIP, subjects completed 15 repetitions using 30% of 1RM. RPE-AM was measured after every third repetition. RPE-AMs were greater (p