A comparison of the immediate effects of resistance, aerobic, and concurrent exercise on postexercise hypotension

A comparison of the immediate effects of resistance, aerobic, and concurrent exercise on postexercise hypotension. The influence of resistance exercise (RE), aerobic exercise (AE), and concurrent exercise (CE) on postexercise hypotension (PEH) is not known. We investigated the immediate blood pressure (BP) lowering effects of exercise after RE, AE, and CE sessions among healthy subjects. Twenty-one men (20.7 ± 0.7 years) performed 4 experimental sessions each in a within-subject design: control (CTL-seated rest for 60 minutes), RE (3 sets at 80% 1RM for 8 exercises, including upper and lower limbs), AE (7-minutes warm-up followed by 50 minutes of cycle ergometer exercise at 65% VO?peak and 3-minute cooldown), and CE (2 sets at 80% 1RM for 6 exercises among those which composed the RE session, plus 20 minutes of cycle ergometer exercise at 65% VO?peak, 7-minute warm-up and 3-minute cooldown, exactly in this order). The total duration of each exercise session was approximately 60 minutes. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were assessed by ambulatory monitoring at rest (20 minutes) and every 10 minutes after the exercise during 120 minutes while in the laboratory. The duration of the decrease in SBP was longer after AE and CE (120 minutes) compared to RE (80 minutes); and for DBP after AE (50 minutes) compared to CE (40 minutes) and RE (20 minutes) (p < 0.05). The magnitude of the decrease in SBP and DBP was similar after all exercise sessions and significantly different from CTL (p < 0.05) (SBP: RE = 4.1 ± 2.0 mm Hg, AE = 6.3 ± 1.3 mm Hg, CE = 5.1 ± 2.2 mm Hg; DBP: RE = 1.8 ± 1.1 mm Hg, AE = 1.8 ± 1.0 mm Hg, CE = 1.6 ± 0.6 mm Hg). It was concluded that exercise sessions combining aerobic and resistance activities are as effective as AE sessions and more effective than RE sessions to promote PEH.     

The effect of rest interval length on bench press performance with heavy vs. light loads

The purpose of the current study was to compare the effect of 3 different rest intervals on multiple sets of the bench press exercise performed with heavy vs. light loads. Sixteen resistance-trained men performed 2 testing sessions each week for 3 weeks. During the first testing session each week, 5 consecutive sets of the bench press were performed with 80% of 1 repetition maximum (1RM) and with a 1-, 2-, or 3-minute rest interval between sets. During the second testing session each week the same procedures were repeated with 50% of 1RM. The total repetitions completed and the sustainability of repetitions were compared between rest conditions and between loads. For each load, resting 3 minutes between sets resulted in significantly greater total repetitions vs. resting 2 minutes (p = 0.000) or 1 minute (p = 0.000) between sets. However, the sustainability of repetitions was not significantly different between loads (p = 0.849). These results can be applied to weekly bench press workouts that undulate between heavy (i.e., 80% 1RM) and light (i.e., 50% 1RM) intensities. When the training goal is maximal strength development, 3 minutes of rest should be taken between sets to avoid significant declines in repetitions. The ability to sustain repetitions while keeping the intensity constant may result in a higher training volume and consequently greater gains in muscular strength.     

Effects of resistance training intensity, volume, and session format on the postexercise hypotensive response

The effect of resistance exercise (RE) on the postexercise systolic and diastolic blood pressure (SBP and DBP) response in young men was investigated. Group 1 (G1) and group 2 (G2) performed three 6 repetition maximum (6RM) sets in a set repetition format for 5 and 6 exercises, respectively. G1 and G2 also performed a circuit and set repetition format session, respectively, using 50% of the 6RM for 3 sets of 12 repetitions (12-repetition protocol). SBP and DBP were determined before and up to 60 minutes postexercise. G1's postexercise SBP demonstrated a significant decrease from its preexercise SBP, lasting 50 minutes after both RE sessions. G2's postexercise SBP demonstrated a significant difference from its preexercise SBP after the 6RM and 12-repetition protocol, lasting 60 and 40 minutes, respectively. The only significant difference in the DBP from rest was at 10 minutes postexercise for G2 after the 12-repetition-per-set protocol. In summary, results indicate that RE intensity affects the duration, but not the magnitude, of the postexercise hypotensive response.     

Short intervals between sets and individuality of muscle damage response

ABSTRACT: Machado, M, Pereira, R, and Willardson, JM. Short intervals between sets and individuality of muscle damage response. J Strength Cond Res 26(11): 2946-2952, 2012-This study examined creatine kinase (CK) activity after resistance exercise sessions in subjects classified as high (HiR), medium (MeR), or low responders (LoR). Two resistance exercise sessions were performed that each involved 4 sets of the biceps curl at 85% of a 1 repetition maximum (1RM) and either 1- or 3-minute rest intervals between sets. High responders and MeR demonstrated significantly greater CK activity after the 1-minute session vs. the 3-minute session. Therefore, the HiR and MeR subjects exhibited less tolerance to resting 1 minute between sets, whereas the CK activity was not significantly different between rest intervals for the LoR subjects. The application of these findings indicates the need to vary the length of the rest interval between sets with the understanding that individuals exhibit varying recuperative abilities and some might be less tolerant of shorter rest intervals between sets.     

Acute effects of heavy preloading on vertical and horizontal jump performance

The purpose of this study was to investigate the acute effects of a heavy dynamic preload, consisting of 1 set of 5 repetition maximum (5RM) back squats, on countermovement vertical jump (VJ) and horizontal jump (HJ) performance. The study also investigated the ability of subjects to learn to apply the effects of the preload over subsequent training sessions. Nineteen (N = 19) resistance-trained men (age = 25.0 +/- 4.8 years; weight = 79.3 +/- 6.6 kg) participated in the study. Each subject took part in 4 practice and 4 testing sessions. The 4 practice sessions were included to allow for any learning effects of VJ and HJ to stabilize and to establish a true 5RM back squat. The 4 testing sessions were included to see if subjects were able to capitalize on the repeat exposure to the protocol. One practice session consisted of a 10-minute warm-up (5 minutes of cycling and 5 minutes of stretching), 2 sets of VJ and HJ (each set of VJ and HJ consisted of 4 jump repetitions) with a 5-minute rest between sets, progressive 5RM back squat evaluation, and 2 final sets of VJ and HJ. Both VJ and HJ increased approximately 2% over the 4 practice sessions, and 5RM back squat strength improved from 164.2 +/- 25.1 kg to 196.9 +/- 23.0 kg (p < or = 0.05). The 4 testing sessions each consisted of the standardized warm-up, 1 set of 4 VJs and HJs, a 5-minute rest, 5RM back squat, a 5-minute rest, and the final set of VJs and HJs. Pre- and post-5RM VJ and HJ order was randomly assigned. The results indicated no significant differences occurred between the mean or maximal values for either VJ or HJ as a consequence of the dynamic preload exercise. In addition, the results reflected an inability of subjects to benefit from the repeated exposure to the heavy dynamic preload exercise protocol.     

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.     

Active intervals between sets of resistance exercises potentiate the magnitude of postexercise hypotension in elderly hypertensive women

Active and passive intervals (AI, PI) between exercise series promote different hemodynamic responses; however, the impact of these intervals on the blood pressure response has not yet been investigated. The objective of this study was to compare the impact of AIs and PIs during resistance exercises with the magnitude of postexercise hypotension (PEH). Elderly hypertensive women (n = 21, 61.2 ± 2 years of age) completed 4 sessions for upper or lower limbs with AI or PI (3 sets, 15 repetitions, 60% load of 15 repetition maximum (RM), and an interval of 90 seconds between sets). Blood pressure was measured 10 minutes before and at 10, 20, 30, 40, and 50 minutes after the exercise sessions. The heart rate at the end of each AI was always significantly higher than that after the PI, but the perceived exertion as measured by the Perceived Exertion Scale (OMNI-RPE) was similar to that of PI exercise protocols. In the lower limb exercises, AI resulted in significantly and consistently higher PEH than in exercises with PI for both systolic (from 20 minutes postexercise) and diastolic (from 10 minutes postexercise) pressures. The upper limb exercises promoted much more discrete PEH in relation to the lower limb exercises, given that the AI promoted significantly higher PEH relative to the PI protocols, but only for systolic PEH and only from 30 minutes postexercise. This is the first time that AIs between sets in a session of resistance exercises have been shown to be a highly effective methodological strategy to increase PEH in elderly hypertensive women.     

The effect of rest interval length on multi and single-joint exercise performance and perceived exertion

The purpose of this study was to compare repetition performance and rating of perceived exertion (RPE) with 1-, 3-, or 5-minute rest intervals between sets of multi and single-joint resistance exercises. Fifteen resistance trained men (23.6 ± 2.64 years, 76.46 ± 7.53 kg, 177 ± 6.98 cm, bench press [BP] relative strength: 1.53 ± 0.25 kg·kg(-1) body mass) completed 12 sessions (4 exercises × 3 rest intervals), with each session involving 5 sets with 10 repetition maximum loads for the free weight BP, machine leg press (LP), machine chest fly (MCF), and machine leg extension (LE) exercises with 1-, 3-, 5-minute rest intervals between sets. The results indicated significantly greater BP repetitions with 3 or 5 minutes vs. 1 minute between sets (p ≤ 0.05); no significant difference was evident between the 3- and 5-minute rest conditions. For the other exercises (i.e., LP, MCF, and LE), significant differences were evident between all rest conditions (1 < 3 < 5; p ≤ 0.05). For all exercises, consistent declines in repetition performance (relative to the first set) were observed for all rest conditions, starting with the second set for the 1-minute condition and the third set for the 3- and 5-minute conditions. Furthermore, significant increases in RPE were evident over successive sets for both the multi and single-joint exercises, with significantly greater values for the 1-minute condition. In conclusion, both multi and single-joint exercises exhibited similar repetition performance patterns and RPE, independent of the rest interval length between sets.     

Effect of rest interval length on repeated 1 repetition maximum back squats

To examine the effects of different rest intervals on the repeatability of 1 repetition maximum (1RM) efforts in the free-weight back squat exercise, 17 weight-trained men served as subjects (mean age 22.0 years). One repetition maximum was tested on each of the first 2 days of testing to establish a stable baseline (1RM = 184.9 kg). Each of the next 3 sessions involved performing 2 1RM back squats, with the rest interval between attempted lifts being either 1, 3, or 5 minutes, assigned in a counterbalanced fashion. For the 1-minute rest interval, 13 of 17 subjects successfully completed the second lift; for the 3-minute rest interval, 16 of 17 were successful; and for the 5-minute rest interval, 15 of 17 were successful. Cochran Q analysis determined no significant difference (p > 0.05) in the ability to repeat a successful maximal-effort back squat when different rest intervals were used. These findings are consistent with the literature for the bench-press exercise and indicate that 1-minute rest intervals are sufficient for recovery between attempted lifts during 1RM testing or training for the free-weight back squat when involving lifters of this caliber.     

Blood pressure and heart rate in patients with ischaemic heart disease receiving nifedipine and propranolol.

A randomised controlled crossover trial was performed to assess the anti-anginal effects of nifedipine and propranolol separately and together. The effects of these treatments on blood pressure and heart rate were assessed at rest and after the cold pressor and mental arithmetic tests. Nifedipine and propranolol together produced the greatest reduction in supine and erect systolic and diastolic blood pressures. Propranolol (480 mg daily) lowered resting systolic/diastolic blood pressures by 7/6 mm Hg and nifedipine (60 mg daily) lowered it by 10/8 mm Hg, while in the erect position the hypotensive effect of these agents averaged 9/8 mm Hg. During the cold pressor test propranolol lowered the maximum pressure by an average of 11/6 mm Hg and nifedipine by 19/10 mm Hg. For the mental arithmetic test, the results were 7/2 mm Hg and 16/7 mm Hg respectively. Propranolol (480 mg daily)reduced supine and erect heart rate by 19 and 25 beats/minute respectively, while nifedipine did not alter heart rate significantly. The favourable haemodynamic responses to nifedipine suggest that it may be of value in the management of hypertension.     

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.     

Chronic conventional resistance exercise reduces blood pressure in stage 1 hypertensive men

To investigate the antihypertensive effects of conventional resistance exercise (RE) on the blood pressure (BP) of hypertensive subjects, 15 middle-aged (46 ± 3 years) hypertensive volunteers, deprived of antihypertensive medication (reaching 153 ± 6/93 ± 2 mm Hg systolic/diastolic BP after a 6-week medication washout period) were submitted to a 12-week conventional RE training program (3 sets of 12 repetitions at 60% 1 repetition maximum, 3 times a week on nonconsecutive days). Blood pressure was measured in all phases of the study (washout, training, detraining). Additionally, the plasma levels of several vasodilators or vasoconstrictors that potentially could be involved with the effects of RE on BP were evaluated pre- and posttraining. Conventional RE significantly reduced systolic, diastolic, and mean BP, respectively, by an average of 16 (p < 0.001), 12 (p < 0.01), and 13 mm Hg (p < 0.01) to prehypertensive values. There were no significant changes of vasoactive factors from the kallikrein-kinin or renin-angiotensin systems. After the RE training program, the BP values remained stable during a 4-week detraining period. Taken together, this study shows for the first time that conventional moderate-intensity RE alone is able to reduce the BP of stage 1 hypertensive subjects free of antihypertensive medication. Moreover, the benefits of BP reduction achieved with RE training remained unchanged for up to 4 weeks without exercise.     

Acute effects of plyometric exercise on maximum squat performance in male athletes

This study examines the acute effects of plyometric exercise on 1 repetition maximum (RM) squat performance in trained male athletes. Twelve men (mean age +/- SD: 20.5 +/- 1.4 years) volunteered to participate in 3 testing sessions separated by at least 6 days of rest. During each testing session the 1RM was assessed on back squat exercise. Before all 3 trials subjects warmed up on a stationary cycle for 5 minutes and performed static stretching. Subjects then performed 5 submaximal sets of 1-8 repetitions before attempting a 1RM lift. Subjects rested for at least 4 minutes between 1RM trials. During the first testing session (T1) subjects performed a series of sets with increasing load until their 1RM was determined. During the second and third testing sessions subjects performed in counterbalanced order either 3 double-leg tuck jumps (TJ) or 2 depth jumps (DJ) 30 seconds before each 1RM attempt. The average 1RM lifts after T1 and testing sessions with TJ or DJ were 139.6 +/- 29.3 kg, 140.5 +/- 25.6 kg, and 144.5 +/- 30.2 kg, respectively (T1 < DJ; p < 0.05). These data suggest that DJ performed before 1RM testing may enhance squat performance in trained male athletes.     

Sympathetic adrenergic blockade effects upon operantly conditioned blood pressure elevations in baboons

Sympathetic adrenergic nervous activity during operantly conditioned hypertension was evaluated by assessing the effects of specific alpha-(phentolamine or phenoxybenzamine) and beta- (propranolol) adrenergic blockers in baboons reinforced for increasing diastolic pressure in daily, 12-h sessions. In the first 10 min of control (no blockade) sessions, mean heart rate increased 24 bpm (21%) above the value for the 10 min immediately prior to the beginning of the sessions; systolic pressure increased 27 mm Hg (22%) and diastolic pressure increased 24 mm Hg (31%). Betablockade eliminated the tachycardia but did not attenuate the increased blood pressure. Alpha-blockade did not attenuate the increased blood pressure significantly either. Combined alpha- and beta-blockade did significantly attenuate the increase in diastolic pressure, but consistent, significant increases in systolic pressure (17 mm Hg, 17%) and diastolic pressure (16 mm Hg, 26%) still occurred. The results support the participation of the sympathetic adrenergic nervous system in producing operantly conditioned blood pressure changes, but the results are also consistent with the additional participation of nonadrenergic factors in operantly conditioned hypertension.     

Influence of rest interval length on acute testosterone and cortisol responses to volume-load-equated total body hypertrophic and strength protocols

ABSTRACT: Villanueva, MG, Villanueva, MG, Lane, CJ, and Schroeder, ET. Influence of rest interval length on acute testosterone and cortisol responses to volume-load-equated total body hypertrophic and strength protocols. J Strength Cond Res 26(10):2755-2764, 2012-We hypothesized that total body strength (S) and hypertrophic (H) resistance training (RT) protocols using relatively short rest interval (RI) lengths between sets will elicit significant acute increases in total testosterone (TT) and cortisol (C) in healthy young men. Six men, 26 (±2.4) years, completed 4 randomized RT sessions, after a control session (R). The S and H protocols were equated for volume load (sets × repetitions × load); S: 8 sets × 3 repetitions at 85% 1RM, H: 3 sets × 10 repetitions at 70% 1RM, for all exercises. The RI used 60 seconds (S60, H60) and 90 seconds (S90, H90). Blood was drawn preexercise (PRE), immediately postexercise (POST), 15 minutes postexercise (15 MIN), and 30 minutes postexercise (30 MIN). The H60 elicited significant increases in TT from PRE (7.32 ± 1.85 ng·ml) to POST (8.87 ± 1.83 ng·ml) (p < 0.01), 15 MIN (8.58 ± 2.15 ng·ml) (p < 0.01), and 30 MIN (8.28 ± 2.16 ng·ml) (p < 0.05). The H90 also elicited significant increases in TT from PRE (8.37 ± 1.93 ng·ml) to POST (9.90 ± 1.25 ng·ml) (p < 0.01) and 15 MIN (9.46 ± 1.27 ng·ml) (p < 0.05). The S60 elicited significant increases in TT from PRE (7.73 ± 1.88 ng·ml) to 15 MIN (8.35 ± 1.64 ng·ml) (p < 0.05), and S90 showed a notable (p < 0.10) difference in TT from PRE (7.96 ± 2.29 ng·ml) to POST (8.75 ± 2.45 ng·ml). All the protocols did not significantly increase C (p > 0.05). Using relatively short RI between RT sets augments the acute TT response to hypertrophic and strength schemes. Shortening RI within high-intensity strength RT may lead to concomitant enhancements in muscle strength and size over a longer period of training.     

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.     

Diastolic dysfunction and intraventricular dyssynchrony are restored by low intensity exercise training in obese men

The aim of this study was to evaluate the impact of a low-intensity training program on subclinical cardiac dysfunction and on dyssynchrony in moderately obese middle aged men. Ten obese and 14 age-matched normal-weight men (BMI: 33.6 ± 1.0 and 24.2 ± 0.5 kg/m(2)) were included. Obese men participated in an 8-week low-intensity training program without concomitant diet. Cardiac function and myocardial synchrony were assessed by echocardiography with tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE). At baseline, obese men showed diastolic dysfunction on standard echocardiography, lower strain values (systolic strain: 15.9 ± 0.9 vs. 18.8 ± 0.3%, diastolic strain rate: 0.81 ± 0.09 vs. 1.05 ± 0.06 s(-1)), and significant intraventricular dyssynchrony (systolic: 13.3 ± 2.1 vs. 5.4 ± 2.1 ms, diastolic: 17.4 ± 3.2 vs. 9.1 ± 2.1 ms) (P < 0.05 vs. controls for all variables). Training improved aerobic fitness, decreased systolic blood pressure and heart rate, and reduced fat mass without weight loss. Diastolic function, strain values (systolic strain: 17.4 ± 0.9%, diastolic strain rate: 0.96 ± 0.12 s(-1)) and intraventricular dyssynchrony (systolic: 3.3 ± 1.7 ms, diastolic: 5.5 ± 3.4 ms) improved significantly after training (P < 0.05 vs. baseline values for all variables), reaching levels similar to those of normal-weight men. In conclusion, in obese men, a short and easy-to-perform low intensity training program restored diastolic function and cardiac synchrony and improved body composition without weight loss.     

Higher muscle performance in adolescents compared with adults after a resistance training session with different rest intervals

The aim of the present study was to compare the effect of 3 different rest intervals between sets on the total training volume, number of repetitions, ratings of perceived exertion (RPE), and resistance to fatigue in adolescents and adults during a resistance training session in the isoinertial chest press exercise. Fifteen male adolescents (15.2 ± 1.2 years; 20.7 ± 2.0 kg·m(-2); Tanner -4; 61.5 ± 8.9, 10 repetition maximum [RM]) and 15 adults (22.2 ± 2.7 years; 23.3 ± 2.0 kg·m(-2); Tanner -5; 84.3 ± 13.5, 10RM) without previous experience with resistance training participated in the study. After 10RM test-retest on 3 different occasions, participants were randomly assigned to a resistance training protocol with 30-, 60-, and 120-second rest interval between sets. The protocol consisted of 3 sets with 10RM. In all studied variables, with exception to total training volume and RPE, adolescents presented superior results as compared with adults (p < 0.001). On the other hand, both adults and adolescents exhibited a higher resistance to fatigue, total training volume, and number of repetitions with a longer rest interval (120 > 60 > 30 seconds) (p < 0.01). Thus, these results indicate that adolescents present a higher recovery capacity between sets in a resistance training session than adults and a longer rest interval results in a higher number of repetitions completed, total training volume, and resistance to fatigue.     

The effects of rest interval length on ratings of perceived exertion during dynamic knee extension exercise

The objective of this study was to examine the effects of rest interval length on perceived exertion and during 3 sets of 10 inertial knee extension repetitions. Thirty healthy men (n = 15) and women (n = 15) volunteers were randomly assigned to 1 of 3 groups (1-, 2-, or 3-minute rest interval length) following the establishment of each subject's 1 repetition maximum (1RM) for inertial knee extension exercise. Subjects in each group performed 3 sets of 10 repetitions at 70% of a theoretical 10RM (based on each subject's 1RM), with a 1-, 2-, or 3-minute rest interval between each set. Perceived exertion was recorded, via the Borg category-ratio scale, from each subject after each repetition of each set. The results demonstrated no significant rest interval length effect on perceived exertion across the 3 sets of 10 repetitions. The results revealed a significantly higher perceived exertion value following the first repetition in set 3 as compared to sets 2 and 1 in all groups. The increase in perceived exertion within each set, as described by the slope, was found to be significantly lowest in set 1, as compared to sets 2 and 3. The major findings of this study demonstrate that perceived exertion significantly increases in a similar manner across 3 sets of 10 knee extension repetitions, despite rest interval lengths of 1-3 minutes.