Time Under Tension Research Articles

Influence of full range of motion vs. equalized partial range of motion training on muscle architecture and mechanical properties.

The purpose of this study was to determine the effect of a 15-week partial range of motion (ROM) resistance training program on the vastus lateralis (VL) architecture and mechanical properties, when the time under tension (TUT) was equalized. Nineteen untrained male subjects were randomly assigned to a control (Control; n = 8) or training (TG; n = 11) group. In the TG, the dominant and nondominant legs were randomly selected to be trained with a full ROM (FULL) or a partial ROM (PART) in an isokinetic dynamometer. Training volume was equalized based on the TUT by manipulating sets and repetitions. The VL muscle architecture was assessed by B-mode ultrasonography at rest and during maximal isometric knee extension contractions (MVCs) at ten knee angles. The VL fascicle force and specific tension were calculated from the MVCs with superimposed stimuli, accounting for the moment arm length, muscle architecture, and antagonist coactivation. The FULL training induced changes in fascicle length (FL) (4.9 ± 2.0%, P < 0.001) and specific tension (25.8 ± 18.7%, P < 0.001). There was a moderate effect of PART training on the physiological cross-sectional area (PCSA) (7.8 ± 4.0%, P < 0.001, dav=0.6) and torque-angle adaptations (average increase 17.7 ± 3.9%, P < 0.05). These results provide evidence that crucial architectural and mechanical muscle adaptations are dependent on the ROM used in strength training. It seems that muscle FL and specific tension can be increased by pure concentric training if greater ROM is used. Conversely, restricting the ROM to shorter muscle lengths promotes a greater PCSA and angle-specific strength adaptations.

Repeticiones máximas y tiempo de tensión entre los ordenes multiarticular para monoarticular y monoarticular para multiarticular en ejercicios resistidos

Objetive: was to analyze maximal repetitions (MR) and time under tension (TUT) between multi-joint to single-joint order and single-joint to multi-joint order in resistance exercises. Methods: Fifteen trained men (23.53 ± 2.07 years, 74.8 ± 5.1 kg, 173.8 ± 4.6cm) performed a 10RM test in the Bench Press (BP) and Arm Extension (AE). After 48h performed maximal re- petitions for the same exercises in different orders, single-joint and multi-joint. In both protocols were measured the maximal repetitions (MR) and time under tension (TUT) only for the last exercise realized. Results: The paired Student's T test showed significant reductions for MR in both analyzed protocols when compared to the 10RM test (p

Determination and comparison of time under tension required to perform 8, 10 and 12-RM loads in the bench press exercise

Summary Study aim: To determine and compare the time under tension (TUT) required to perform 8, 10 and 12 repetition maximum (RM) loads in the bench press exercise. Material and methods: Twenty men (24.17 ± 4.69 years) were selected intentionally and properly. We included in the study physically active individuals, with a weekly frequency of physical activity of at least two days for six months, and excluded individuals with injury or pain that could interfere with the correct execution of the exercise and individuals with positive PAR-Q. The 10-RM test consisted in performing ten consecutive repetitions with maximum overload and the highest speed in bench press exercise on the Smith machine. After 48 h, 10-RM sets were performed with the load obtained in the 10-RM load testing. The TUT in 10-RM was verified through kinematics using the timing technique of the Kinovea software. Results: The RM loads and TUT obtained during the retest session showed normal distribution between subjects. However, no significant differences were found between the loads 8, 10 and 12-RM within and between subjects (p &lt; 0.05). The verified TUT showed a difference from 8 to 10-RM and from 8 to 12-RM, but no significant difference was found between TUT protocols for 10 and 12-RM (p &lt; 0.05). Conclusion: The study results enable evaluation of TUT in bench press exercise on the Smith machine for the study sample, allowing, for this group, the prediction and control of training intensity through the TUT.

The impact of repetition mechanics on the adaptations resulting from strength-, hypertrophy- and cluster-type resistance training.

PurposeThe purpose of this study was to examine the acute and chronic training responses to strength-, hypertrophy- and cluster-type resistance training.MethodsThirty-four trained males were assigned to a strength [STR: 4 × 6 repetitions, 85 % of one repetition maximum, (1RM), 900 s total rest], hypertrophy (HYP: 5 × 10 repetitions, 70 % 1RM, 360 s total rest), cluster 1 (CL-1: 4 × 6/1 repetitions, 85 % 1RM, 1400 s total rest), and cluster 2 (CL-2: 4 × 6/1 repetitions, 90 % 1RM, 1400 s total rest) regimens which were performed twice weekly for a 6-week period. Measurements were taken before, during and following the four workouts to investigate the acute training stimulus, whilst similar measurements were employed to examine the training effects before and after the intervention.ResultsThe improvements in 1RM strength were significantly greater for the STR (12.09 ± 2.75 %; p < 0.05, d = 1.106) and CL-2 (13.20 ± 2.18 %; p < 0.001, d = 0.816) regimens than the HYP regimen (8.13 ± 2.54 %, d = 0.453). In terms of the acute responses, the STR and CL-2 workouts resulted in greater time under tension (TUT) and impulse generation in individual repetitions than the HYP workout (p < 0.05). Furthermore, the STR (+3.65 ± 2.54 mmol/L−1) and HYP (+6.02 ± 2.97 mmol/L−1) workouts resulted in significantly greater elevations in blood lactate concentration (p < 0.001) than the CL-1 and CL-2 workouts.ConclusionCL regimens produced similar strength improvements to STR regimens even when volume load was elevated (CL-2). The effectiveness of the STR and CL-2 regimens underlines the importance of high loads and impulse generation for strength development.

New exercise-integrated technology can monitor the dosage and quality of exercise performed against an elastic resistance band by adolescents with patellofemoral pain: an observational study.

Is the exercise-integrated Bandcizer™ system feasible for recording exercise dosage (time under tension (TUT) and repetitions) and pain scores among adolescents with patellofemoral pain? Do adolescents practise the exercises as prescribed (TUT and repetitions)? Do adolescents accurately report the exercises they do in an exercise diary? Observational feasibility study. Twenty adolescents between 15 and 19 years of age with patellofemoral pain. Participants were prescribed three exercise sessions per week (one with and two without supervision) for 6 weeks. The exercises included three hip and one knee exercise with an elastic resistance band. Participants were instructed to perform three sets with a predefined TUT (3seconds concentric; 2seconds isometric; 3seconds eccentric; 2seconds pause), equating to 80seconds for 10 repetitions (one set). The exercise-integrated system consisted of a sensor attached to the elastic resistance band that was connected to the Bandtrainer app on an electronic tablet device. Pain intensity was reported on a visual analogue scale on the app. Participants also completed a self-report exercise diary. No major problems were reported with the system. Participants performed 2541 exercise sets during the 6 weeks; 5% were performed with the predefined TUT (ie, within 10seconds of the 80-second target) and 90% were performed below the target TUT. On average, the participants received 15% of the instructed exercise dosage based on TUT. The exercise dosage reported in the exercise diaries was 2.3 times higher than the TUT data from the electronic system. Pain intensity was successfully collected in 100% of the exercise sets. The system was feasible for adolescents with patellofemoral pain. The system made it possible to capture detailed data about the TUT, repetitions and sets during home-based exercises together with pain intensity before and after each exercise. [Rathleff MS, Bandholm T, McGirr KA, Harring SI, Sørensen AS, Thorborg K (2016) New exercise-integrated technology can monitor the dosage and quality of exercise performed against an elastic resistance band by adolescents with patellofemoral pain: an observational study.Journal of Physiotherapy62: 159-163].

Einfluss der Belastungsdauer beim HIT-Krafttraining

High intensity training (HIT) is a variant of single-set training. It is becoming increasingly popular in strength training practice. Contrary to the large number of research on multiple-set training, empirical investigations addressing HIT are rare. There is evidence that an important factor for muscle hypertrophy is the muscle time under tension (TUT). However, scientific knowledge about the optimal length of the TUT is lacking. Therefore, the aim of the present study was to compare the effects of a rather short TUT (20–40 s) with a rather long TUT (50–70 s) during HIT strength training. Nine experienced recreational sportsmen completed a ten week HIT strength training either with the short or the long TUT. The participants performed a whole-body training program with nine strength exercises twice a week. After the intervention they showed significant improvements of 5-RM (p &lt; 0.05; 0.780 ≤ η2 ≤ 0.906) for all strength exercises. The short TUT intervention group increased their strength performance by 20.6%–44.2%, whereas the long TUT intervention group improved by 12.3%–33.7%. There were no statistically significant differences between both intervention groups (p &gt; 0.05; 0.007 ≤ η2 ≤ 0.340). With respect to body composition, the participants increased their body weight from pre- to posttest (p &lt; 0.05; η2 = 0.515), which could be explained by the significant growth of muscle mass (p &lt; 0.05; η2 = 0.634). Statistically significant differences between both intervention groups were not found for any of the investigated body composition parameters (p &gt; 0.05; 0.039 ≤ η2 ≤ 0.123). In conclusion, the study verifies the high effectiveness of HIT strength training. Moreover, the results indicate that the TUT within a HIT strength training has no practically relevant effect, if the TUT amounts between 20–70 s until first concentric muscle failure.

The majority are not performing home-exercises correctly two weeks after their initial instruction—an assessor-blinded study

Introduction. Time-under-tension (TUT) reflects time under load during strength training and is a proxy of the total exercise dose during strength training. The purpose of this study was to investigate if young participants are able to reproduce TUT and exercise form after two weeks of unsupervised exercises.Material and Methods. The study was an assessor-blinded intervention study with 29 participants. After an initial instruction, all participants were instructed to perform two weeks of home-based unsupervised shoulder abduction exercises three times per week with an elastic exercise band. The participants were instructed in performing an exercise with a predefined TUT (3 s concentric; 2 s isometric; 3 s eccentric; 2 s break) corresponding to a total of 240 s of TUT during three sets of 10 repetitions. After completing two weeks of unsupervised home exercises, they returned for a follow-up assessment of TUT and exercise form while performing the shoulder abduction exercise. A stretch sensor attached to the elastic band was used to measure TUT at baseline and follow-up. A physiotherapist used a pre-defined clinical observation protocol to determine if participants used the correct exercise form.Results. Fourteen of the 29 participants trained with the instructed TUT at follow-up (predefined target: 240 s ±8%). Thirteen of the 29 participants performed the shoulder abduction exercise with a correct exercise form. Seven of the 29 participants trained with the instructed TUT and exercise form at follow-up.Conclusion. The majority of participants did not use the instructed TUT and exercise form at follow-up after two weeks of unsupervised exercises. These findings emphasize the importance of clear and specific home exercise instructions if participants are to follow the given exercise prescription regarding TUT and exercise form as too many or too few exercise stimuli in relation to the initially prescribed amount of exercise most likely will provide a misinterpretation of the actual effect of any given specific home exercise intervention.

Acute response to cluster sets in trained and untrained men.

In traditional sets (TRD) repetitions are performed continuously, whereas cluster sets (CLU) allow a brief rest between groups of repetitions. We investigated the acute mechanical, metabolic, and hormonal response to CLU in men. Twelve resistance-trained (RT) and 11 untrained (UT) men performed TRD (4×10 repetitions with 2min rest) and CLU [4×(2×5) with 1.5min rest between sets 30s rest between clusters] at 70% 1RM back squat in random order. Seven days separated trials. Average power and time under tension (TUT) were calculated. Blood was sampled pre, sets 1, 2, and 3; immediate post-exercise, 5, 15, 30, 60min post-exercise for blood lactate, total testosterone (TT), free testosterone (FT), growth hormone (GH), and cortisol. CLU produced greater average power at an increasing number of repetitions over each set with greater total volume load. TUT was shorter for RT and lower for CLU in repetitions 1, 6, 7, 8. Blood lactate was higher Set 2 through 30min in TRD. RT had higher TT; however, the time course was similar between RT and UT. TT and FT increased immediate post-exercise and remained elevated 30min in both conditions. GH was significantly greater during TRD with a similar pattern observed in both conditions. Cortisol was significantly lower at 30min in CLU. CLU allowed greater total volume load, shorter TUT, greater average power, similar anabolic hormonal response, and less metabolic stress. The acute response was similar despite training status.

Detecting repetitions and time features in resistance training using triaxial accelerometry

Accurately determining resistance-training parameters is crucial to gain knowledge about the training process and to evaluate training interventions. To current knowledge, no method exists to automatically detect a series of features in a repetition training session using one three-dimensional accelerometer. In this study, a specific algorithm was used to detect the number of repetitions and different time features. Features determined by the acceleration algorithm were compared to a reference system using a linear wire encoder to detect movements. A total of 50 healthy participants were randomly assigned to three different groups (maximal strength, hypertrophy, and muscular endurance) and executed three different resistance-training exercises (bench press, leg press, and trunk flexion). Results of both measurement systems were compared for agreement using Bland–Altman plots, regarding repetition numbers, TUT (time under tension) in concentric, eccentric, and isometric contraction forms and total TUT (sum...

Adherence to commonly prescribed, home-based strength training exercises for the lower extremity can be objectively monitored using the bandcizer.

The purpose of this study was to investigate the validity of automatically stored exercise data from the elastic band sensor compared with those of a gold-standard stretch sensor during exercises commonly used for rehabilitation of the hip and knee. The design was a concurrent validity study. Participants performed 3 sets of 10 repetitions of 6 exercises with both sensors attached to the same elastic exercise band. These were knee extension, knee flexion, hip abduction and adduction, hip flexion, and hip external rotation. Agreement between methods was calculated for date, time of day, repetitions, total and single repetition, and contraction phase-specific time under tension (TUT). Files from the elastic band sensor contained identical dates, time of day, and number of repetitions for each exercise set compared with those for the gold standard. Total TUT and total single repetition TUT were highly correlated with the stretch sensor (r = 0.83-0.96) but lower for contraction phase-specific TUTs (r = 0.45-0.94). There were systematic differences between the methods ranging from 0.0 to 2.2 seconds (0.0-6.3%) for total TUT and total single repetition TUT, and between 0.0 and 3.3 seconds (0.0-33.3%) for contraction phase-specific TUTs. The elastic band sensor is a valid measure of date, time of day, number of repetitions and sets, total TUT, and total single repetition TUT during commonly used home-based strength training exercises. However, the elastic band sensor seems unable to validly measure TUT for specific contraction phases.

Exercise associated hormonal signals as powerful determinants of an effective fat mass loss.

Obesity management for achieving an effective weight loss includes dietary modification and exercise [resistance (strength), endurance (cardiovascular) or intervals training (high-intensity intermittent exercise)]. Regular exercise acutely increases fat oxidation, which induces loss of fat mass and increases energy expenditure. Moreover, it has a positive effect on the physical (improved insulin sensitivity, lipid profile, etc.) and mental health (mood, cognition, memory, sleep, etc.). Endocrine responses to muscle actions are affected by many factors, including the exercise muscle groups (lower and upper body), load/volume, time-under tension, and rest-period intervals between sets, training status, gender, and age. The aim of this review is to summarize, evaluate, and clarify the literature data focusing on the endocrine responses to different types of exercise, including the frequency, intensity, and type of movement with regard to the fat loss strategies. Many studies have investigated anabolic [growth hormone, insulin-like growth factor-1 (IGF-1), testosterone] and gluco- and appetite- regulatory (insulin, cortisol, ghrelin) hormone responses and adaptations of skeletal muscles to exercise. Muscle tissue is a critical endocrine organ, playing important role in the regulation of several physiological and metabolic events. Moreover, we are also describing the response of some other substances to exercise, such as myokines [irisin, apelin, brain-derived neurotrophic factor (BDNF), myostatin, and fibroblast growth factor 21 (FGF21)]. It is proposed that reducing intra-abdominal fat mass and increasing cardiorespiratory fitness through improving nutritional quality, reducing sedentary behavior, and increase the participation in physical activity/exercise, might be associated with clinical benefits, sometimes even in the absence of weight loss.

High force development augments skeletal muscle signalling in resistance exercise modes equalized for time under tension.

How force development and time under tension (TUT) during resistance exercise (RE) influence anabolic signalling of skeletal muscle is incompletely understood. We hypothesized that high force development during RE is more important for post-exercise-induced signalling than submaximal and fatiguing RE with lower force development but similar TUT. Twenty-two male subjects (24 ± 6 years, 181 ± 9 cm, 79 ± 2 kg) performed three distinct RE modes in the fed state with equal TUT but distinct force output: (i) maximal eccentric RE (ECC, n = 7) three sets, eight reps, 100% eccentric dynamic force; (ii) standard RE (STD, n = 7), three sets, 10 reps, 75% dynamic force; and (iii) high fatiguing single-set RE (HIT, n = 8), 20 reps, 100% eccentric-concentric force; vastus lateralis biopsies were collected at baseline, 15, 30, 60, 240 min and 24 h after RE, and the signalling of mechanosensitive and mammalian target of rapamycin (mTOR)-related proteins was determined. The phosphorylation levels of pFAK(Tyr397), pJNK(Thr183/Tyr185), pAKT(Thr308/Ser473), pmTOR(Ser2448), p4E-BP1(Thr37/46), p70s6k(Thr389)/(Ser421/Thr424) and pS6(Ser235/236) were significantly higher in ECC than those in STD and HIT at several time points (P < 0.01). pJNK(Thr183/Tyr185) and pS6(Ser235/236) levels were significantly higher in type II myofibres in ECC compared with STD and HIT. HIT exerted throughout the weakest signalling response. We conclude that high force development during acute RE is superior for anabolic skeletal muscle signalling than fatiguing RE with lower force output but similar TUT. Our results suggest that this response is substantially driven by the higher activation of type II myofibres during RE.

Concentric and Eccentric Time-Under-Tension during Strengthening Exercises: Validity and Reliability of Stretch-Sensor Recordings from an Elastic Exercise-Band

BackgroundTotal, single repetition and contraction-phase specific (concentric and eccentric) time-under-tension (TUT) are important exercise-descriptors, as they are linked to the physiological and clinical response in exercise and rehabilitation.ObjectiveTo investigate the validity and reliability of total, single repetition, and contraction-phase specific TUT during shoulder abduction exercises, based on data from a stretch-sensor attached to an elastic exercise band.MethodsA concurrent validity and interrater reliability study with two raters was conducted. Twelve participants performed five sets of 10 repetitions of shoulder abduction exercises with an elastic exercise band. Exercises were video-recorded to assess concurrent validity between TUT from stretch-sensor data and from video recordings (gold standard). Agreement between methods was calculated using Limits of Agreement (LoA), and the association was assessed by Pearson correlation coefficients. Interrater reliability was calculated using intraclass correlation coefficients (ICC 2.1).ResultsTotal, single repetition, and contraction-phase specific TUT – determined from video and stretch-sensor data – were highly correlated (r>0.99). Agreement between methods was high, as LoA ranged from 0.0 to 3.1 seconds for total TUT (2.6% of mean TUT), from -0.26 to 0.56 seconds for single repetition TUT (6.9%), and from -0.29 to 0.56 seconds for contraction-phase specific TUT (13.2-21.1%). Interrater reliability for total, single repetition and contraction-phase specific TUT was high (ICC>0.99). Interrater agreement was high, as LoA ranged from -2.11 to 2.56 seconds for total TUT (4.7%), from -0.46 to 0.50 seconds for single repetition TUT (9.7%) and from -0.41 to 0.44 seconds for contraction-phase specific TUT (5.2-14.5%).ConclusionData from a stretch-sensor attached to an elastic exercise band is a valid measure of total and single repetition time-under-tension, and the procedure is highly reliable. This method will enable clinicians and researchers to objectively quantify if home-based exercises are performed as prescribed, with respect to time-under-tension.

Difference in Kinematics and Kinetics Between High- and Low-Velocity Resistance Loading Equated by Volume: Implications for Hypertrophy Training

Although it is generally accepted that a high load is necessary for muscle hypertrophy, it is possible that a low load with a high velocity results in greater kinematics and kinetics than does a high load with a slow velocity. The purpose of this study was to determine if 2 training loads (35 and 70% 1 repetition maximum [1RM]) equated by volume, differed in terms of their session kinematic and kinetic characteristics. Twelve subjects were recruited in this acute randomized within-subject crossover design study. Two bouts of a half-squat exercise were performed 1 week apart, one with high load-low velocity (HLLV = 3 sets of 12 reps at 70% 1RM) and the other with low-load high-velocity (LLHV = 6 sets of 12 reps at 35% 1RM). Time under tension (TUT), average force, peak force (PF), average power (AP), peak power (PP), work (TW), and total impulse (TI) were calculated and compared between loads for the eccentric and concentric phases. For average eccentric and concentric single repetition values, significantly (p < 0.05) greater (∼15-22%) PP outputs were associated with the LLHV loading, whereas significantly greater (∼7-61%) values were associated with the HLLV condition for most other variables of interest. However, in terms of total session kinematics and kinetics, the LLHV protocol resulted in significantly greater (∼16-61%) eccentric and concentric TUT, PF, AP, PP, and TW. The only variable that was significantly greater for the HLLV protocol than for the LLHV protocol was TI (∼20-24%). From these results, it seems that the LLHV protocol may offer an equal if not better training stimulus for muscular adaptation than the HLLV protocol, because of the greater time under tension, power, force, and work output when the total volume of the exercise is equated.

Comparison of Methods to Quantify Volume During Resistance Exercise

The purpose of this investigation was to compare 4 different methods of calculating volume when comparing resistance exercise protocols of varying intensities. Ten Appalachian State University students experienced in resistance exercise completed 3 different resistance exercise protocols on different days using a randomized, crossover design, with 1 week of rest between each protocol. The protocols included 1) hypertrophy: 4 sets of 10 repetitions in the squat at 75% of a 1-repetition maximum (1RM) (90-second rest periods); 2) strength: 11 sets of 3 repetitions at 90% 1RM (5-minute rest periods); and 3) power: 8 sets of 6 repetitions of jump squats at 0% 1RM (3-minute rest periods). The volume of resistance exercise completed during each protocol was determined with 4 different methods: 1) volume load (VL) (repetitions [no.] x external load [kg]); 2) maximum dynamic strength volume load (MDSVL) (repetitions [no.] x [body mass--shank mass (kg) + external load (kg)]); 3) time under tension (TUT) (eccentric time +milliseconds] + concentric time +milliseconds]); and 4) total work (TW) (force [N] x displacement [m]). The volumes differed significantly (p , 0.05) between hypertrophy and strength in comparison with the power protocol when VL and MDSVL were used to determine the volume of resistance exercise completed. Furthermore, significant differences in TUT existed between all 3 resistance exercise protocols. The TW calculated was not significantly different between the 3 protocols. These data imply that each method examined results in substantially different values when comparing various resistance exercise protocols involving different levels of intensity.

The effects of varying time under tension and volume load on acute neuromuscular responses

The purpose of this study was to examine the effects of different methods of measuring training volume, controlled in different ways, on selected variables that reflect acute neuromuscular responses. Eighteen resistance-trained males performed three fatiguing protocols of dynamic constant external resistance exercise, involving elbow flexors, that manipulated either time-under-tension (TUT) or volume load (VL), defined as the product of training load and repetitions. Protocol A provided a standard for TUT and VL. Protocol B involved the same VL as Protocol A but only 40% concentric TUT; Protocol C was equated to Protocol A for TUT but only involved 50% VL. Fatigue was assessed by changes in maximum voluntary isometric contraction (MVIC), interpolated doublet (ID), muscle twitch characteristics (peak twitch, time to peak twitch, 0.5 relaxation time, and mean rates of force development and twitch relaxation). All protocols produced significant changes (P <or= 0.05) in the measures considered to reflect neuromuscular fatigue, with the exception of ID. Fatigue was related to an increase in either TUT or VL with greater fatigue, as reflected by MVIC and peripheral measures, being associated with differences in TUT. The lack of change in ID suggests that fatigue was more related to peripheral than central mechanisms. It was concluded that the load and contraction velocities of the repetitions have different effects on acute neuromuscular responses and should, therefore, be clearly calculated when describing training volume for dynamic constant external resistance exercise training.

Time under Tension and Blood Lactate Response during Four Different Resistance Training Methods

Mechanical stimuli have often been suggested to be the major determinant of resistance training adaptations; however, some studies suggested that metabolic changes also play an important role in the gains of muscle size and strength. Several resistance training methods (RTM) have been employed with the purpose of manipulating mechanical and metabolic stimuli; however, information about their physiological effects are scarce. The objective of this study was to compare the time under tension (TUT) and blood lactate responses among four different RTM reported in the literature. The four RTM were performed in a knee extension machine at 10 repetition maximum (RM) load by 12 recreationally trained young men. The RTM tested were: 10RM, super-slow (SL-subjects performed one 60-second repetition with 30 seconds for eccentric and 30 seconds for concentric phase), functional isometrics (FI-in each repetition, a five-second maximal isometric contraction was executed with the knees fully extended) and adapted vascular occlusion (VO-subjects performed a 20-second maximal isometric contraction with the knees fully extended and immediately proceeded to normal isoinertial lifts). According to the results, all RTM produced significant increases in blood lactate levels. However, blood lactate responses during FI (4.48+/-1.57 mM) and VO (4.23+/-1.66 mM) methods were higher than the SL method (3.41+/-1.14 mM). The TUT for SL (60 s), FI (56.33+/-6.46 s), and VO (53.08+/-4.76 s) methods were higher than TUT for 10RM (42.08+/-3.18 s). Additionally, TUT for the SL method was higher than TUT during the VO method. Therefore, the SL method may not be recommended if one wants to provide a high metabolic stimulus. The FI method appeared to be especially effective in promoting both type of stimuli.