Monitoring exercise intensity during resistance training using the session RPE scale

This study investigated the reliability of the session rating of perceived exertion (RPE) scale to quantify exercise intensity during high-intensity (H), moderate-intensity (M), and low-intensity (L) resistance training. Nine men (24.7 +/- 3.8 years) and 10 women (22.1 +/- 2.6 years) performed each intensity twice. Each protocol consisted of 5 exercises: back squat, bench press, overhead press, biceps curl, and triceps pushdown. The H consisted of 1 set of 4-5 repetitions at 90% of the subject's 1 repetition maximum (1RM). The M consisted of 1 set of 10 repetitions at 70% 1RM, and the L consisted of 1 set of 15 repetitions at 50% 1RM. RPE was measured following the completion of each set and 30 minutes postexercise (session RPE). Session RPE was higher for the H than M and L exercise bouts (p < or = 0.05). Performing fewer repetitions at a higher intensity was perceived to be more difficult than performing more repetitions at a lower intensity. The intraclass correlation coefficient for the session RPE was 0.88. The session RPE is a reliable method to quantify various intensities of resistance training.     

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 相似文献   

Influence of exercise order on the number of repetitions performed and perceived exertion during resistance exercise in women

The purpose of this study was to investigate the influence of different resistance exercise orders on the number of repetitions performed to failure and on the ratings of perceived exertion (RPE) in trained women. Twenty-three women with a minimum of 2 years of resistance training experience volunteered to participate in the study (age, 24.2 +/- 4.5 years; weight, 56.9 +/- 4.7 kg; height, 162.3 +/- 5.9 cm; percent body fat, 18.2 +/- 2.9%; body mass index, 22.2 +/- 2 kg x m(-2)). Data were collected in 2 phases: (a) determination of a 1 repetition maximum (1RM) for the leg-press (LP), bench press (BP), leg extension (LE), seated machine shoulder press (SP), leg curl (LC), and seated machine triceps extension (TE); and (b) execution of 3 sets, with 2-minute rest intervals between sets and exercises, until fatigue using 80% of 1RM in 2 exercise sequences of the exact opposite order--Sequence A: BP, SP, TE, LP, LE, and LC, and Sequence B: LC, LE, LP, TE, SP, and BP. The RPE (Borg CR-10) was accessed immediately after each sequence and analyzed using a Wilcoxon test. A 2-way analysis of variance with repeated measurements, followed by a post hoc Fisher least significant difference test where indicated was used to analyze the number of repetitions per set of each exercise during the 2 sequences. The RPE was not significantly different between the sequences. The mean number of repetitions per set was always less when an exercise was performed later in the exercise sequence. The data indicate that in trained women, performance of both large- and small-muscle group exercises is affected by exercise sequence.     

The effects of amino acid supplementation on muscular performance during resistance training overreaching

The purpose of this study was to examine the effects of amino acid supplementation on muscular strength, power, and high-intensity endurance during short-term resistance training overreaching. Seventeen resistance-trained men were randomly assigned to either an amino acid (AA) or placebo (P) group and underwent 4 weeks of total-body resistance training consisting of two 2-week phases of overreaching (phase 1: 3 x 8-12 repetitions maximum [RM], 8 exercises; phase 2: 5 x 3-5 RM, 5 exercises). Muscle strength, power, and high-intensity endurance were determined before (T1) and at the end of each training week (T2-T5). One repetition maximum squat and bench press decreased at T2 in P (5.2 and 3.4 kg, respectively) but not in AA, and significant increases in 1 RM squat and bench press were observed at T3-T5 in both groups. A decrease in the ballistic bench press peak power was observed at T3 in P but not AA. The fatigue index during the 20-repetition jump squat assessment did not change in the P group at T3 and T5 (fatigue index = 18.6 and 18.3%, respectively) whereas a trend for reduction was observed in the AA group (p = 0.06) at T3 (12.8%) but not T5 (15.2%; p = 0.12). These results indicate that the initial impact of high-volume resistance training overreaching reduces muscle strength and power, and it appears that these reductions are attenuated with amino acid supplementation. In addition, an initial high-volume, moderate-intensity phase of overreaching followed by a higher intensity, moderate-volume phase appears to be very effective for enhancing muscle strength in resistance-trained men.     

A comparison of 3 different rest intervals on the exercise volume completed during a workout

The purpose of this research was to compare differences between 3 different rest intervals on the squat and bench press volume completed during a workout. Fifteen college-aged men volunteered to participate in this study (age 20.73 +/- 2.60 years; body mass 80.73 +/- 10.80 kg). All subjects performed 3 testing sessions, during which 4 sets of the squat and bench press were performed with an 8 repetition maximum (8RM) load. During each testing session, the squat and bench press were performed with a 1, 2, or 5-minute rest interval between sets. Volume was defined as the total number of repetitions completed over 4 sets for each rest condition. Statistical analysis was conducted separately for the squat and bench press. One-way repeated analyses of variance with Bonferroni post hocs demonstrated significant differences between each rest condition for both exercises tested (p < 0.05). The 5-minute rest condition resulted in the highest volume completed, followed in descending order by the 2- and 1-minute rest conditions. The ability to perform a higher volume of training with a given load may stimulate greater strength adaptations.     

Strength changes during an in-season resistance-training program for football

The purpose of this study was to examine the effects of both intensity and volume of training during a 2 d.wk(-1) in-season resistance-training program (RTP) for American football players. Fifty-three National Collegiate Athletic Association Division III football players were tested in the 1 repetition maximum (1RM) bench press and 1RM squat on the first day of summer training camp (PRE) and during the final week of the regular season (POST). Subjects were required to perform 3 sets of 6-8 repetitions per exercise. Significant strength improvements in squat were observed from PRE (155.0 +/- 31.8 kg) to POST (163.3 +/- 30.0 kg), whereas no PRE to POST changes in bench press were seen (124.7 +/- 21.0 kg vs.123.9 +/- 18.6 kg, respectively). Training volume and training compliance were not related to strength improvement. Further analysis showed that athletes training at >or=80% of their PRE 1RM had significantly greater strength improvements than athletes training at <80% of their PRE 1RM, for both bench press and squat. Strength improvements can be seen in American football players, during an in-season RTP, as long as exercise intensity is >or=80% of the 1RM.     

The effect of rest interval length on the sustainability of squat and bench press repetitions

The purpose of this study was to compare the effect of 3 different rest intervals on the sustainability of squat and bench press repetitions over 5 consecutive sets performed with a 15 repetition maximum (RM)-load. Fifteen college-age men with previous resistance training experience were tested weekly over a period of 3 weeks. During each testing session, 5 consecutive sets of the squat and the bench press were performed with a 30-second, 1-minute, or 2-minute rest interval between sets. For each exercise, significant declines in repetitions occurred between the first and the fifth sets (p = 0.000). For the squat, a significant difference in the ability to sustain repetitions occurred between the 30-second and 2-minute rest condition (p = 0.003). However, differences were not significant between the 30-second and 1-minute rest conditions (p = 0.986) and between the 1-minute and 2-minute rest conditions (p = 0.042). For the bench press, significant differences in the ability to sustain repetitions occurred between the 30-second and 2-minute rest conditions (p = 0.000) and between the 1-minute and 2-minute rest conditions (p = 0.000). However, differences were not significant between the 30-second and 1-minute rest conditions (p = 0.019). For each exercise, the number of repetitions completed on the first set was not sustained over subsequent sets, irrespective of the rest condition. These results suggest that when short rest intervals are used to develop muscular endurance, the intensity should be lowered over subsequent sets to sustain repetitions within the range conducive to this training goal.     

Excess postexercise oxygen consumption following acute aerobic and resistance exercise in women who are lean or obese

Seventeen women were divided into lean (19.5 +/- 0.5 years; 22.2 +/- 0.6 kg.m(-2)) and obese (20.4 +/- 0.5 years; 34.9 +/- 2.1 kg.m(-2)) groups. On completion of a submax cycle ergometer test and 10-repetition maximum (10RM) of 5 exercises on a Smith machine, subjects returned for 2 exercise sessions during menses. Session 1 consisted of performing 3 sets of 10 repetitions at 70% of the predetermined 10RM for the following exercises: squat, calf raises, bench press, upright row, and shoulder press. Session 2 consisted of cycling at 60-65% VO2max for a duration that would expend the same number of calories as the resistance session. Postexercise respiratory exchange ratio and EPOC magnitude/duration were similar for both groups. These findings indicate that women who are lean or obese will respond similarly to exercise at similar relative intensities and that aerobic and resistance exercise of equal caloric expenditure will elicit similar EPOC responses.     

Occlusion training increases muscular strength in division IA football players

The purpose of this study was to investigate the effectiveness of 4 weeks of low-intensity resistance training with blood-flow occlusion on upper and lower body muscular hypertrophy and muscular strength in National Collegiate Athletic Association Division IA football players. There were 32 subjects (average age 19.2 ± 1.8 years) who were randomized to an occlusion group or control group. The athletes performed 4 sets of bench press and squat in the following manner with or without occlusion: 30 repetitions of 20% predetermined 1 repetition maximum (1RM), followed by 3 sets of 20 repetitions at 20% 1RM. Each set was separated by 45 seconds. The training duration was 3 times per week, after the completion of regular off-season strength training. Data collected included health history, resting blood pressure, pretraining and posttraining bench press and squat 1RM, upper and lower chest girths, upper and lower arm girths, thigh girth, height, and body mass. The increases in bench press and squat 1RM (7.0 and 8.0%, respectively), upper and lower chest girths (3 and 3%, respectively), and left upper arm girth were significantly greater in the experiment group (p < 0.05). Occlusion training could provide additional benefits to traditional strength training to improve muscular hypertrophy and muscular strength in collegiate athletes.     

Maximal power at different percentages of one repetition maximum: influence of resistance and gender

National Collegiate Athletic Association Division I athletes were tested to determine the load at which maximal mechanical output is achieved. Athletes performed power testing at 30, 40, 50, 60, and 70% of individual 1 repetition maximum (1RM) in the squat jump, bench press, and hang pull exercises. Additionally, hang pull power testing was performed using free-form (i.e., barbell) and fixed-form (i.e., Smith machine) techniques. There were differences between genders in optimal power output during the squat jump (30-40% of 1RM for men; 30-50% of 1RM for women) and bench throw (30% of 1RM for men; 30-50% of 1RM for women) exercises. There were no gender or form interactions during the hang pull exercise; maximal power output during the hang pull occurred at 30-60% of 1RM. In conclusion, these results indicate that (a) gender differences exist in the load at which maximal power output occurs during the squat jump and bench throw; and (b) although no gender or form interactions occurred during the hang pull exercise, greater power could be generated during fixed-form exercise. In general, 30% of 1RM will elicit peak power outputs for both genders and all exercises used in this study, allowing this standard percentage to be used as a starting point in order to train maximal mechanical power output capabilities in these lifts in strength trained athletes.     

Comparison of muscle force production using the Smith machine and free weights for bench press and squat exercises

The Smith machine (SM) (vertical motion of bar on fixed path; fixed-form exercise) and free weights (FWs) (free-form path) are commonly used strength training modes. Exercisers may need to alternate between types of equipment, depending on testing, training, rehabilitation, and/or the exercisers' goals. The purposes of this study were to compare muscle force production for SM and FWs using a 1 repetition maximum (1RM) for the parallel back squat and supine bench press exercises and to predict the 1RM for one mode from 1RM on the other mode. Men (n = 16) and women (n = 16) alternately completed 1RM testing for squat and bench press using SM and FWs. Analyses of variance (type of equipment x sex) and linear regression models were calculated. A significant difference was found between bench press and squat 1RMs for each mode of equipment for all participants. The squat 1RM was greater for the SM than the FWs; conversely, the bench 1RM was greater for FWs than the SM. When sex was considered, bench 1RM for FWs was greater than SM for men and women. The squat 1RM was greater for SM than FWs for women only. The 1RM on one mode of equipment was the best predictor of 1RM for the other mode. For both sexes, the equation SM bench 1RM (in kilograms) = -6.76 + 0.95 (FW bench 1RM) can be used. For women only, SM squat 1RM (in kilograms) = 28.3 + 0.73 (FW squat 1RM). These findings provide equations for converting between SM and FW equipment for training.     

Role of concentric force in limiting improvement in muscular strength

We hypothesized that resistance training with combined eccentric and concentric actions, and concentric action only, should yield similar changes in muscular strength. Subjects in a free weight group trained three times a week for 12 wk with eccentric and concentric actions (FW, n = 16), a second group trained with concentric-only contractions using hydraulic resistance (HY; n = 12), and a control group did not train (n = 11). Training for FW and HY included five sets of supine bench press and upright squat at an intensity of 1-6 repetition maximum (RM) plus five supplementary exercises at 5-10 RM for a total of 20 sets per session for approximately 50 min. Testing at pre-, mid-, and posttraining included 1) 1 RM bench press and squat with and 2) without prestretch using free weights; 3)isokinetic peak force and power for bench press and squat at 5 degrees/s, and isotonic peak velocity and power for bench press with 20-kg load and squat with 70-kg load; 4) hydraulic peak bench press force and power, and peak knee extension torque and power at fast and slow speeds; and 5) surface anthropometry (fatfolds and girths to estimate upper arm and thigh volume and muscle area). Changes in overall fatness, muscularity, and muscle + bone cross-sectional area of the limbs did not differ between groups (P greater than 0.05). Improvements in free weight bench press and squat were similar (P greater than 0.05) in FW (approximately 24%) and HY (approximately 22%, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Predicting maximal strength in trained postmenopausal woman

The purpose of this study was to present an equation that accurately predicts 1 repetition maximum (RM) over a wide range of repetitions to fatigue (RTF) for 4 different machine resistance exercises in postmenopausal women. Seventy trained women (age = 57.4 +/- 3.1 years) performed maximal and submaximal repetitions on leg press, bench press, rowing, and leg adduction machines at the conclusion of a 2-year training program. Maximal repetitions were performed on each exercise in the following ranges: 3-5RM, 6-10RM, 11-15RM, and 16-20RM. Special regard was taken to maintain the identical execution of each test (i.e., range of motion, starting angle, speed of movement). One cubic polynomial (w(i) [0.988-0.0000584 r(i)(3) + 0.00190 r(i)(2) + 0.0104 r(i),] where w(i) is the load of measurement I, and r(i) is the number of repetitions) accurately predicted 1RM from RTF with mean absolute differences between actual 1RM and predicted 1RM for the 4 exercises of 1.5-3.1% and with coefficients of variation of <3.3%. Equation accuracy was independent of the exercise type or the number of RTF. Thus, this study supported the validity of RTF to adequately estimate 1RM over a wide range of repetitions and within different exercises in trained, older female subjects.     

Plasma volume change during heavy-resistance weight lifting

Blood samples were obtained from six young men before, and over a 60-min period following a bout of heavy-resistance weight lifting to determine changes in plasma volume. Weight lifting consisted of three sets of four exercises (arm curl, bench press, bent-arm row, and squat) performed using 70% of one-repetition maximum for as many repetitions as possible. Plasma volume change was determined from haematocrit and haemoglobin concentration. During weight lifting, mean oxygen uptake and heart rate were 1.96 L X min-1 and 158 bt X min-1, respectively. Plasma volume was decreased -14.3% (p less than 0.05) immediately following exercise and -7.0% (p less than 0.05) at 15 min into recovery, but had returned to the resting level within 30 min. It was concluded that heavy-resistance weight lifting elicits a significant decrease in plasma volume, which is similar in magnitude to that observed during running and cycling at 80-95% of maximal oxygen uptake.     

Effect of two different rest period lengths on the number of repetitions performed during resistance training

The purpose of this study was to compare the effects of 2 different rest period lengths during a resistance training session with the number of repetitions completed per set of each exercise, the volume completed over 3 sets of each exercise, and the total volume during a training session. Fourteen experienced, weight-trained men volunteered to participate in the study. All subjects completed 2 experimental training sessions. Both sessions consisted of 3 sets of 8 repetitions with an 8 repetition maximum resistance of 6 upper body exercises performed in a set manner (wide grip lat pull-down, close grip pull-down, machine seated row, barbell row lying on a bench, dumbbell seated arm curl, and machine seated arm curl). The 2 experimental sessions differed only in the length of the rest period between sets and exercises: 1 session with a 1-minute and the other with a 3-minute rest period. For all exercises, results demonstrate a significantly lower total number of repetitions for all 3 sets of an exercise when 1-minute rest periods were used (p < or = 0.05). The 3- and 1-minute protocols both resulted in a significant decrease from set 1 to set 3 in 4 of the 6 exercises (p < or = 0.05), whereas the 1-minute protocol also demonstrated a significant decrease from set 1 to set 2 in 2 of the 6 exercises (p < or = 0.05). The results indicate that, during a resistance training session composed of all upper body exercises, 1-minute rest periods result in a decrease in the total number of repetitions performed compared with 3-minute rest periods between sets and exercises.     

Effect of a learning trial on self-selected resistance training load

Previous research has shown that individuals self-select loads for resistance training that falls below the accepted threshold for overload and do not lift to volitional fatigue. The purpose of this study was to determine the effects of a resistance training learning trial on self-selected resistance training load. A control group (5 women, 3 men) and a learning group of (4 women, 4 men) novice lifters were recruited. The control group (CG) received an orientation to selected strength machines (seated bench, leg extension, back row, biceps curl, triceps extension, shoulder press). On a subsequent training day, CG self-selected a training load, while blinded to the actual loads. The learning group (LG) received an initial orientation and also was tested for estimated 1 repetition maximum (1RM) for the seated bench press. On a subsequent day, the LG completed 2 sets of the seated bench press at 75% of estimated 1RM and were encouraged to lift until failure. On a third day, LG subjects completed a self-selected trial identical to that of the CG. Both groups were assessed for estimated 1RM for each exercise on a separate day following all trials. Comparisons between CG and LG were made using independent-means t tests and adjusted using Bonferroni's equation (p < 0.01). While subjects selected a bench press load that was 21% greater for LG (63.4 +/- 6.4% 1RM) compared to the CG (50.3 +/- 12.0%), there was no statistical significance. There were no significant differences in self-selected load for any of the other exercises. There were also no significant differences for number of repetitions or rate of perceived exertion between groups. We conclude that a learning trial of the bench press exercise to increase self-selected workload is not enough to change load self-selection.     

Influence of exercise order on the number of repetitions performed and perceived exertion during resistance exercises

This study examined the performance effects of exercise order during a resistance-training session composed of only upper-body exercises. The 10 repetition maximum of 14 men and 4 women with at least 6 months of previous weight-training experience was determined for 5 upper-body exercises. Each subject then completed 2 training sessions separated by 48 hours in a counterbalanced crossover design. One session began with exercises of the large-muscle group and progressed to exercises of the small-muscle group (sequence A), whereas the other session was performed with the opposite exercise sequence (sequence B). The exercise order for sequence A was free-weight bench press (BP), machine lat pull-down (LPD), seated machine shoulder press (SP), standing free-weight biceps curl (BC) with a straight bar, and seated machine triceps extension (TE). The exercise order for sequence B was TE, BC, SP, LPD, and BP. During both sequences, 3 sets of each exercise were performed to concentric failure, with 2-minute recovery intervals between sets and exercises. Performing exercises of both the large- and the small-muscle groups at the end of an exercise sequence resulted in significantly fewer repetitions in the 3 sets of an exercise. This decrease in the number of repetitions performed was especially apparent in the third set when an exercise was performed last in an exercise sequence.     

Fiber type composition and capillary density in relation to submaximal number of repetitions in resistance exercise

The purpose of this study was to investigate the relationship between skeletal muscle fiber type composition and the maximum number of repetitions performed during submaximal resistance exercise. Twelve young men performed a maximum repetitions test at 85% of 1 repetition maximum (1RM) in the leg press, which was repeated after 1 week. Seven days after the second 85% 1RM test, they performed a maximum repetitions test at 70% of 1RM in the leg press. This test, at 70% 1RM, was repeated 7 days later. One week before the initiation of the testing sessions, a biopsy sample was obtained from the vastus lateralis muscle and analyzed for fiber type distribution, fiber cross-sectional area, and capillary density (capillaries x mm(2)). A low and nonsignificant relationship was found between the fiber type distribution or percent fiber type area and the number of repetitions performed at either 70% or 85% 1RM. Moreover, the number of repetitions performed at 70% or 85% of 1RM was not related significantly with 1RM strength. In contrast, the number of repetitions performed at 70% 1RM was significantly correlated with the number of capillaries per mm(2) of muscle cross-sectional area (r = 0.70; p = 0.01). These results suggest that fiber type composition is not the major biological variable regulating the number of repetitions performed in submaximal resistance exercise. Rather, it seems that submaximal strength performance depends on muscle capillary density, which is linked with the endurance capacity of the muscle tissue.