Participatory development of an mHealth intervention delivered in general practice to increase physical activity and reduce sedentary behaviour of patients with prediabetes and type 2 diabetes (ENERGISED).

BACKGROUND: The escalating global prevalence of type 2 diabetes and prediabetes presents a major public health challenge. Physical activity plays a critical role in managing (pre)diabetes; however, adherence to physical activity recommendations remains low. The ENERGISED trial was designed to address these challenges by integrating mHealth tools into the routine practice of general practitioners, aiming for a significant, scalable impact in (pre)diabetes patient care through increased physical activity and reduced sedentary behaviour. METHODS: The mHealth intervention for the ENERGISED trial was developed according to the mHealth development and evaluation framework, which includes the active participation of (pre)diabetes patients. This iterative process encompasses four sequential phases: (a) conceptualisation to identify key aspects of the intervention; (b) formative research including two focus groups with (pre)diabetes patients (n = 14) to tailor the intervention to the needs and preferences of the target population; (c) pre-testing using think-aloud patient interviews (n = 7) to optimise the intervention components; and (d) piloting (n = 10) to refine the intervention to its final form. RESULTS: The final intervention comprises six types of text messages, each embodying different behaviour change techniques. Some of the messages, such as those providing interim reviews of the patients' weekly step goal or feedback on their weekly performance, are delivered at fixed times of the week. Others are triggered just in time by specific physical behaviour events as detected by the Fitbit activity tracker: for example, prompts to increase walking pace are triggered after 5 min of continuous walking; and prompts to interrupt sitting following 30 min of uninterrupted sitting. For patients without a smartphone or reliable internet connection, the intervention is adapted to ensure inclusivity. Patients receive on average three to six messages per week for 12 months. During the first six months, the text messaging is supplemented with monthly phone counselling to enable personalisation of the intervention, assistance with technical issues, and enhancement of adherence. CONCLUSIONS: The participatory development of the ENERGISED mHealth intervention, incorporating just-in-time prompts, has the potential to significantly enhance the capacity of general practitioners for personalised behavioural counselling on physical activity in (pre)diabetes patients, with implications for broader applications in primary care.

Effects of 36 hours of sleep deprivation on military-related tasks: Can ammonium inhalants maintain performance?

INTRODUCTION: A lack of sleep can pose a risk during military operations due to the associated decreases in physical and cognitive performance. However, fast-acting ergogenic aids, such as ammonia inhalants (AI), may temporarily mitigate those adverse effects of total sleep deprivation (TSD). Therefore, the present study aimed to investigate the acute effect of AI on cognitive and physical performance throughout 36 hours of TSD in military personnel. METHODS: Eighteen male military cadets (24.1 ± 3.0 y; 79.3 ± 8.3 kg) performed 5 identical testing sessions during 36 hours of TSD (after 0 [0], 12 [-12], 24 [-24], and 36 [-36] hours of TSD), and after 8 [+8] hours of recovery sleep. During each testing session, the following assessments were conducted: Epworth sleepiness scale (ESS), simple reaction time (SRT), shooting accuracy (SA), rifle disassembling and reassembling (DAS), and countermovement jump height (JH). Heart rate (HR) was continuously monitored during the SA task, and a rating of perceived exertion (RPE) was obtained during the JH task. At each time point, tests were performed twice, either with AI or without AI as control (CON), in a counterbalanced order. RESULTS: There was faster SRT (1.6%; p < 0.01) without increasing the number of errors, higher JH (1.5%; p < 0.01), lower RPE (9.4%; p < 0.001), and higher HR (5.0%; p < 0.001) after using AI compared to CON regardless of TSD. However, neither SA nor DAS were affected by AI or TSD (p > 0.05). Independent of AI, the SRT was slower (3.2-9.3%; p < 0.001) in the mornings (-24, +8) than in the evening (-12), JH was higher (3.0-4.7%, p < 0.001) in the evenings (-12, -36) than in the mornings (0, -24, +8), and RPE was higher (20.0-40.1%; p < 0.001) in the sleep-deprived morning (-24) than all other timepoints (0, -12, -36, +8). Furthermore, higher ESS (59.5-193.4%; p < 0.001) was reported at -24 and -36 than the rest of the time points (0, -12, and + 8). CONCLUSION: Although there were detrimental effects of TSD, the usage of AI did not reduce those adverse effects. However, regardless of TSD, AI did result in a short-term increase in HR, improved SRT without affecting the number of errors, and improved JH while concurrently decreasing the RPE. No changes, yet, were observed in SA and DAS. These results suggest that AI could potentially be useful in some military scenarios, regardless of sleep deprivation.

Validity of Commercially Available Punch Trackers.

ABSTRACT: Omcirk, D, Vetrovsky, T, Padecky, J, Malecek, J, and Tufano, JJ. Validity of commercially available punch trackers. J Strength Cond Res 37(11): 2273-2281, 2023-This study determined how well data from commercially available punch trackers (Corner, Hykso, and StrikeTec) related to gold-standard velocity and force measures during full-contact punches. In a quasi-randomized order, 20 male subjects performed 6 individual rear straight punches, rear hooks, and rear uppercuts against a wall-mounted force plate. Punch tracker variables were compared with the peak force of the force plate and to the peak (QPV) and mean velocity (QMV) assessed through Qualisys 3-dimensional tracking. For each punch tracker variable, Pearson's correlation coefficient, mean absolute percentage error (MAPE), and mean percentage error (MPE) were calculated. There were no strong correlations between punch tracker data and gold-standard force and velocity data. However, Hykso "velocity" was moderately correlated with QMV ( r = 0.68, MAPE 0.64, MPE 0.63) and QPV ( r = 0.61, MAPE 0.21, MPE -0.06). Corner Power G was moderately correlated with QMV ( r = 0.59, MAPE 0.65, MPE 0.58) and QPV ( r = 0.58, MAPE 0.27, MPE -0.09), but Corner "velocity" was not. StrikeTec "velocity" was moderately correlated with QMV ( r = 0.56, MAPE 1.49, MPE 1.49) and QPV ( r = 0.55, MAPE 0.46, MPE 0.43). Therefore, none of the devices fared particularly well for all of their data output, and if not willing to accept any room for error, none of these devices should be used. Nevertheless, these devices and their proprietary algorithms may be updated in the future, which would warrant further investigation.

mHealth intervention delivered in general practice to increase physical activity and reduce sedentary behaviour of patients with prediabetes and type 2 diabetes (ENERGISED): rationale and study protocol for a pragmatic randomised controlled trial.

BACKGROUND: The growing number of patients with type 2 diabetes and prediabetes is a major public health concern. Physical activity is a cornerstone of diabetes management and may prevent its onset in prediabetes patients. Despite this, many patients with (pre)diabetes remain physically inactive. Primary care physicians are well-situated to deliver interventions to increase their patients' physical activity levels. However, effective and sustainable physical activity interventions for (pre)diabetes patients that can be translated into routine primary care are lacking. METHODS: We describe the rationale and protocol for a 12-month pragmatic, multicentre, randomised, controlled trial assessing the effectiveness of an mHealth intervention delivered in general practice to increase physical activity and reduce sedentary behaviour of patients with prediabetes and type 2 diabetes (ENERGISED). Twenty-one general practices will recruit 340 patients with (pre)diabetes during routine health check-ups. Patients allocated to the active control arm will receive a Fitbit activity tracker to self-monitor their daily steps and try to achieve the recommended step goal. Patients allocated to the intervention arm will additionally receive the mHealth intervention, including the delivery of several text messages per week, with some of them delivered just in time, based on data continuously collected by the Fitbit tracker. The trial consists of two phases, each lasting six months: the lead-in phase, when the mHealth intervention will be supported with human phone counselling, and the maintenance phase, when the intervention will be fully automated. The primary outcome, average ambulatory activity (steps/day) measured by a wrist-worn accelerometer, will be assessed at the end of the maintenance phase at 12 months. DISCUSSION: The trial has several strengths, such as the choice of active control to isolate the net effect of the intervention beyond simple self-monitoring with an activity tracker, broad eligibility criteria allowing for the inclusion of patients without a smartphone, procedures to minimise selection bias, and involvement of a relatively large number of general practices. These design choices contribute to the trial's pragmatic character and ensure that the intervention, if effective, can be translated into routine primary care practice, allowing important public health benefits. TRIAL REGISTRATION: ClinicalTrials.gov (NCT05351359, 28/04/2022).

Does a linear position transducer placed on a stick and belt provide sufficient validity and reliability of countermovement jump performance outcomes?

Manufacturers recommend that linear position transducers (LPTs) should be placed on the side of a barbell (or wooden dowel) to measure countermovement jump (CMJ) height, but the validity and reliability of this placement have not been compared to other attachment sites. Since this recommended attachment site is far from the centre of mass, a belt attachment where the LPT is placed between the feet may increase the validity and reliability of CMJ data. Thirty-six physical education students participated in the study (24.6 ± 4.3 years; 177.0 ± 7.7 cm; 77.2 ± 9.0 kg). Parameters from the two LPT attachments (barbell and belt) were simultaneously validated to force plate data, where the nature of bias was analysed (systematic vs random). The within-session and between-session reliability of both attachment sites were compared to force plate data using a test-retest protocol of two sets of 5 CMJs separated by 7 days. The LPT provided highly reliable and valid measures of peak force, mean force, mean power, and jump height, where the bias was mostly systematic (r2 > 0.7; ICC > 0.9). Peak velocity, mean velocity, and peak power were in very good agreement with the force plate and were highly reliable (r2 > 0.5; ICC > 0.7). Therefore, both attachment sites produced similar results with a systematic bias compared to force plate data. Thus, both attachment sites seem to be valid for assessing CMJs when the measuring tool and site remain consistent across measurements. However, if LPT data are to be compared to force plate data, recalculation equations should be used.

Comparison of Traditional and Rest-Redistribution Sets on Indirect Markers of Muscle Damage Following Eccentric Exercise.

ABSTRACT: Merrigan, JJ, Jones, MT, Malecek, J, Padecky, J, Omcirk, D, Xu, N, Peñailillo, L, and Tufano, JJ. Comparison of traditional and rest-redistribution sets on indirect markers of muscle damage following eccentric exercise. J Strength Cond Res 36(7): 1810-1818, 2022-The purpose was to investigate the effect of rest-redistribution (RR) on muscle damage after eccentric knee extensions. After 2 weeks of eccentric familiarization, 11 resistance-trained men performed 2 work-matched isokinetic unilateral eccentric knee extension protocols at 60°·s-1 using a crossover design, separated by 7 days. Subjects performed 40 repetitions with 285 seconds of rest using traditional sets (TS; 4 sets of 10 with 95 seconds of interset rest) and RR (RR; 20 sets of 2 with 15 seconds of interset rest). Muscle morphology, tensiomyography, range of motion, perceived soreness, and strength were measured before and 0, 24, 48, 72, and 96 hour after RR and TS. There were no protocol × time interactions (p < 0.05). When collapsed across protocol and compared to baseline, echo intensity of the proximal vastus lateralis was 7 ± 9% greater at 0 hour (p = 0.042), echo intensity of the distal vastus lateralis was 6 ± 7% and 9 ± 7% greater at 0 hour (p = 0.048) and 24 hour (p < 0.001), respectively, and passive ROM was 2 ± 1% lower at 48 hour (p = 0.043) after exercise. No other differences existed over time for any other variable. Thus, contrary to concentric performance where RR likely plays a large role in maintaining performance, RR during eccentric isokinetic resistance training does not strongly influence exercise performance and indications of subsequent muscle damage.

Assisted Jumping in Healthy Older Adults: Optimizing High-Velocity Training Prescription.

ABSTRACT: Tufano, JJ, Vetrovsky, T, Stastny, P, Steffl, M, Malecek, J, and Omcirk, D. Assisted jumping in healthy older adults: optimizing high-velocity training prescription. J Strength Cond Res 36(6): 1518-1523, 2022-Because older adults benefit from power training, training strategies for athletes such as supramaximal velocity-assisted jumping could also be useful for older adults. However, optimizing-assisted exercise prescription in older adults remains uninvestigated. Therefore, the purpose of this study was to determine the effects of different bodyweight (BW) assistance levels on jumping force and velocity in healthy older adults. Twenty-three healthy older adults (67.6 ± 7.6 years, 167.0 ± 8.8 cm, 72.7 ± 14.3 kg, and 27.1 ± 6.9% body fat) performed 5 individual countermovement jumps at BW, 90, 80, 70, and 60% of BW. Jumps were performed on a force plate, which provided peak take-off force (TOF), flight time, and peak impact force. A linear position transducer measured peak concentric velocity (PV). The rating of perceived exertion (RPE) was also assessed after each condition. Take-off force was greater during BW than all other conditions, 90 and 80% were greater than 70 and 60%, but there were no differences between 80 and 90% or between 70 and 60%. The FT progressively increased at all assistance levels, and PV was faster for all assistance levels than BW, with no differences between assistance levels. Impact force was greater during BW than 80, 70, and 60% and was greater during 90% than 60%. The RPE was less than BW during all assistance conditions but was the least during 70%. Implementing assisted jumping between 70 and 80% of BW in older adults likely provides the ideal combination of force, velocity, and RPE.

Validity of Load-Velocity Relationship to Predict 1 Repetition Maximum During Deadlifts Performed With and Without Lifting Straps: The Accuracy of Six Prediction Models.

ABSTRACT: Jukic, I, García-Ramos, A, Malecek, J, Omcirk, D, and Tufano, JJ. Validity of load-velocity relationship to predict 1 repetition maximum during deadlifts performed with and without lifting straps: The accuracy of six prediction models. J Strength Cond Res 36(4): 902-910, 2022-This study aimed to compare the accuracy of six 1 repetition maximum (1RM) prediction models during deadlifts performed with (DLw) and without (DLn) lifting straps. In a counterbalanced order, 18 resistance-trained men performed 2 sessions that consisted of an incremental loading test (20-40-60-80-90% of 1RM) followed by 1RM attempts during the DLn (1RM = 162.0 ± 26.9 kg) and DLw (1RM = 179.0 ± 29.9 kg). Predicted 1RMs were calculated by entering both group and individualized mean concentric velocity of the 1RM (V1RM) into an individualized linear and polynomial regression equations, which were derived from the load-velocity relationship of 5 ([20-40-60-80-90% of 1RM], i.e., multiple-point method) or 2 ([40 and 90% of 1RM] i.e., 2-point method) incremental warm-up sets. The predicted 1RMs were deemed highly valid if the following criteria were met: trivial to small effect size, practically perfect r, and low absolute errors (<5 kg). The main findings revealed that although prediction models were more accurate during the DLn than DLw, none of the models provided an accurate estimation of the 1RM during both DLn (r = 0.92-0.98; absolute errors: 6.6-8.1 kg) and DLw (r = 0.80-0.93; absolute errors: 12.4-16.3 kg) according to our criteria. Therefore, these results suggest that the 1RM for both DLn and DLw should not be estimated through the recording of movement velocity if sport professionals are not willing to accept more than 5 kg of absolute errors.

Magnitude and Reliability of Velocity and Power Variables During Deadlifts Performed With and Without Lifting Straps.

ABSTRACT: Jukic, I, García-Ramos, A, Malecek, J, Omcirk, D, and Tufano, JJ. Magnitude and reliability of velocity and power variables during deadlifts performed with and without lifting straps. J Strength Cond Res 36(5): 1177-1184, 2022-This study aimed to compare the magnitude and reliability of mean velocity (MV), peak velocity (PV), mean power (MP), and peak power (PP) between deadlifts performed with (DLw) and without (DLn) lifting straps. Sixteen resistance-trained men performed a DLn 1-repetition maximum (1RM) session followed by 4 experimental sessions (2 with each deadlift variant in a randomized order). Each experimental session comprised lifts at 20, 40, 60, and 80% of the DLn 1RM. No significant differences were found between DLw and DLn for MV, MP, PV, and PP at any load (p = 0.309-1.00; g = 0.00-0.19). All mechanical variables showed an acceptable reliability for both deadlift conditions at each relative load (coefficient of variation [CV] <8%; intraclass correlation coefficient [ICC] > 0.70; g < 0.5) with the only exception of MV at 60% 1RM for DLw (ICC = 0.62) and at 40% 1RM for DLn (ICC = 0.65). Furthermore, MV and PV generally had lower within-subject CV (CV = 3.56-5.86%) than MP and PP (CV = 3.82-8.05%) during both deadlift conditions. Our findings suggest that sport professionals might not need to consider implementing lifting straps with the aim to maximize velocity and power outputs with submaximal loads in a deadlift exercise. Because all mechanical variables measured showed an acceptable level of reliability for both DLw and DLn, they can all be used to track changes in performance during the deadlift exercise. However, velocity variables were slightly more consistent (lower CV), which makes them more appropriate to track DLw and DLn performance changes.

The Effects of High Mineral Alkaline Water Consumed Over Three Consecutive Days on Reaction Time Following Anaerobic Exercise - A Randomized Placebo-Controlled Crossover Pilot Study.

Drinking alkaline water after intense anaerobic exercise may enhance both cognitive and physical performance. This study aimed to investigate the effect of high mineral alkaline water consumed over three consecutive days on reaction time after anaerobic exercise in twelve healthy young males (aged 21.1 ± 1.3 years) with a valid sports medical examination. Participants were excluded when they took any medications or performance-enhancing supplements for the period of at least four weeks before the study commenced. Participants were randomly divided into two groups in this double-blind, placebo-controlled crossover pilot study. They ingested either alkaline water (AW) or regular table water ( RTW) for three consecutive days before anaerobic exercise. The anaerobic exercise consisted of two 2-min high-intensity step-tests with a passive rest interval of 3 minutes between the two bouts of exercise. Performance in the step-test (W), reaction time for visual and auditory signals, the rate of perceived exertion (RPE), urine specific gravity, and lactate concentration were analysed. No effect of AW was found on reaction time and the other variables except anaerobic performance. An-aerobic performance was significantly higher after ingestion of AW in both step-tests (p < 0.05). The ingestion of AW for three consecutive days before anaerobic exercise seems to positively affect anaerobic performance.

Punch Trackers: Correct Recognition Depends on Punch Type and Training Experience.

To determine the ability of different punch trackers (PT) (Corner (CPT), Everlast (EPT), and Hykso (HPT)) to recognize specific punch types (lead and rear straight punches, lead and rear hooks, and lead and rear uppercuts) thrown by trained (TR, n = 10) and untrained punchers (UNTR, n = 11), subjects performed different punch combinations, and PT data were compared to data from video recordings to determine how well each PT recognized the punches that were actually thrown. Descriptive statistics and multilevel modelling were used to analyze the data. The CPT, EPT and HPT detected punches more accurately in TR than UNTR, evidenced by a lower percentage error in TR (p = 0.007). The CPT, EPT, and HPT detected straight punches better than uppercuts and hooks, with a lower percentage error for straight punches (p < 0.001). The recognition of punches with CPT and HPT depended on punch order, with earlier punches in a sequence recognized better. The same may or may not have occurred with EPT, but EPT does not allow for data to be exported, meaning the order of individual punches could not be analyzed. The CPT and HPT both seem to be viable options for tracking punch count and punch type in TR and UNTR.

Morning fatigue and structured exercise interact to affect non-exercise physical activity of fit and healthy older adults.

BACKGROUND: Exercise training is crucial for maintaining physical and mental health in aging populations. However, as people participate in structured exercise training, they tend to behaviorally compensate by decreasing their non-exercise physical activity, thus potentially blunting the benefits of the training program. Furthermore, physical activity of older adults is substantially influenced by physical feelings such as fatigue. Nevertheless, how older people react to day-to-day fluctuations of fatigue and whether fatigue plays a role in non-exercise physical activity compensation is not known. Thus, the purpose of this study was twofold: (1) To explore whether the volume and intensity of habitual physical activity in older adults were affected by morning fatigue. (2) To investigate the effect of attending power and resistance exercise sessions on the levels of non-exercise physical activity later that day and the following day. METHODS: Twenty-eight older adults wore an accelerometer during a 4-week low-volume, low-intensity resistance and power training program with three exercise sessions per week and for 3 weeks preceding and 1 week following the program. During the same period, the participants were prompted every morning, using text messages, to rate their momentary fatigue on a scale from 0 to 10. RESULTS: Greater morning fatigue was associated with lower volume (p = 0.002) and intensity (p = 0.017) of daily physical activity. Specifically, one point greater on the fatigue scale was associated with 3.2 min (SE 1.0) less moderate-to-vigorous physical activity. Furthermore, attending an exercise session was associated with less moderate-to-vigorous physical activity later that day by 3.7 min (SE 1.9, p = 0.049) compared to days without an exercise session. During the next day, the volume of physical activity was greater, but only in participants with a body mass index up to 23 (p = 0.008). CONCLUSIONS: Following low-volume exercise sessions, fit and healthy older adults decreased their non-exercise physical activity later that day, but this compensation did not carry over into the next day. As momentary morning fatigue negatively affects daily physical activity, we suggest that the state level of fatigue should be monitored during intensive exercise programs, especially in less fit older adults with increased fatigability.

Overspeed Stimulus Provided by Assisted Jumping Encourages Rapid Increases in Strength and Power Performance of Older Adults.

Following a 4-week control period, 24 older men and women (55-91 years) attended a 4-week progressive jumping program to determine whether assisted jumping could be safely and effectively implemented as a novel stimulus in healthy older adults. Bodyweight countermovement jump performance, isometric and isokinetic strength, postural stability, and exercise enjoyment were assessed before the control period, before the training intervention, and after the training intervention. Following the 4-week intervention, eccentric quadriceps strength increased by 19 N·m (95% confidence interval [2, 36], p = .013), bodyweight countermovement jump height increased by 1.7 cm (95% CI [0.5, 2.9], p < .001), postural sway improved by 2.1 mm/s (95% CI [0.3, 4.0], p = .026), and the participants' perceived exercise enjoyment improved (p = .026). Therefore, using assisted jumping to induce an overspeed training stimulus in a jump training program resulted in similar performance improvements as in previous studies in older populations but with less training volume and a shorter training duration.

Ergogenic effects of lifting straps on movement velocity, grip strength, perceived exertion and grip security during the deadlift exercise.

It is possible that during resistance training, a weak link in the kinetic chain could possibly result in under-stimulated prime movers. Since grip strength can be a limiting factor during multiple sets of various pulling exercises such as deadlifts, it is important to determine how lifting straps can affect mechanical performance, grip strength, perceived exertion and perceived grip security and power. Sixteen males (24.4 ± 2.3 y; 181.6 ± 5.8 cm; 86.6 ± 8.2 kg) completed three protocols: 4 sets of 4 repetitions without straps using 80% of their without-straps 1-repetition max (DLnn); the same protocol with straps based on their without-straps 1-repetition max (DLwn); and the same with straps based on their with-straps 1-repetitions max (DLww). DLwn allowed for greater mean velocity (MV) and peak velocity (PV) than DLnn and DLww, while MV and PV were greater during DLnn than DLww. The magnitude of grip fatigue was lower during DLwn and DLww than DLn. Perceived grip security and power were greater during DLwn and DLww compared to DLn. Perceived exertion was lower during DLwn than DLnn and DLww. These findings suggest that the use of lifting straps during deadlifts allows for a better maintenance of grip strength, faster grip strength recovery following training, and greater perceived grip security and power than deadlifts performed without lifting straps, while also increasing mechanical performance and decreasing the perceived exertion. Therefore, the ergogenic potential of the lifting straps has important training implications and should be considered during RT involving the deadlift exercise and possibly other pulling exercises.

Impact of Rest-Redistribution on Fatigue During Maximal Eccentric Knee Extensions.

Redistributing long inter-set rest intervals into shorter but more frequent rest intervals generally maintains concentric performance, possibly due to improved energy store maintenance. However, eccentric actions require less energy than concentric actions, meaning that shorter but more frequent sets may not affect eccentric actions to the same degree as concentric actions. Considering the increased popularity of eccentric exercise, the current study evaluated the effects of redistributing long inter-set rest periods into shorter but more frequent rest periods during eccentric only knee extensions. Eleven resistance-trained men performed 40 isokinetic unilateral knee extensions at 60°·s-1 with 285 s of total rest using traditional sets (TS; 4 sets of 10 with 95 s inter-set rest) and rest-redistribution (RR; 20 sets of 2 with 15 s inter-set rest). Before and during exercise, muscle oxygenation was measured via near-infrared spectroscopy, and rating of perceived exertion (RPE) was recorded after every 10th repetition. There were no differences between protocols for peak torque (RR, 241.58±47.20 N; TS, 231.64±48.87 N; p=0.396) or total work (RR, 215.26±41.47 J; TS, 209.71±36.02 J; p=0.601), but moderate to large effect sizes existed in later repetitions (6,8,10) with greater peak torque during RR (d=0.66-1.19). For the entire session, RR had moderate effects on RPE (RR, 5.73±1.42; TS, 6.09±1.30; p=0.307; d=0.53) and large effects on oxygen saturation (RR, 5857.4±310.0; TS, 6495.8±273.8; p=0.002, d=2.13). Therefore, RR may maintain peak torque or total work during eccentric exercise, improve oxygen utilization at the muscle, and reduce the perceived effort.

The Use of Lifting Straps Alters the Entire Load-Velocity Profile During the Deadlift Exercise.

Jukic, I, García-Ramos, A, Malecek, J, Omcirk, D, and Tufano, JJ. The use of lifting straps alters the entire load-velocity profile during the deadlift exercise. J Strength Cond Res 34(12): 3331-3337, 2020-This study aimed to compare the one repetition maximum (1RM) and load-velocity (LV) profile between deadlifts performed with (DLw) and without (DLn) lifting straps. The full individual LV relationship of 20 men (age: 24.3 ± 2.4 years; body height: 180.6 ± 6.9 cm; body mass: 85.8 ± 8.0 kg) was randomly evaluated during 2 separate sessions for the DLw and DLn via an incremental loading test. One repetition maximum was greater (p < 0.001; g = 0.56, 95% confidence interval = [0.32, 0.79]) for DLw (177.0 ± 28.9 kg) compared with DLn (160.6 ± 26.0 kg). A highly linear relationship between mean velocity (MV) and %1RM was observed for both conditions (R > 0.95; SEE < 6.18 %1RM for pooled data and R > 0.98; SEE < 3.6 %1RM for individual data). However, MV associated with each %1RM was greater for DLn, and these differences were accentuated as the loading magnitude increased (g = 0.30-1.18). One repetition maximum was strongly associated between both conditions (r = 0.875 [0.71, 0.95]), whereas MV at 1RM (r = 0.21 [-0.25, 0.60]) was unrelated between conditions. The slope of the LV profiles (r = 0.845 [0.64, 0.94]) was correlated, but differed (g = 0.41 [0.16, 0.66]) between DLw and DLn, whereas the mean test velocity of all loads was unrelated (r = 0.270 [-0.20, 0.64]). An individual LV profile should be created for each athlete in the same condition that are going to be used in training to obtain a more precise estimation of the submaximal relative loads.

Traditional sets versus rest-redistribution: a laboratory-controlled study of a specific cluster set configuration at fast and slow velocities.

This study investigated redistributing long inter-set rest intervals into shorter but more frequent intervals at 2 different concentric velocities. Resistance-trained men performed 4 randomised isokinetic unilateral knee extension protocols, 2 at 60°·s-1 and 2 at 360°·s-1. At each speed, subjects performed 40 repetitions with 285 s of rest using traditional sets (TS; 4 sets of 10 with 95 s of inter-set rest) and rest-redistribution (RR; 20 sets of 2 with 15 s inter-set rest). Before and at 2, 5, and 10 min after exercise, tensiomyography (TMG) and oxygenation (near-infrared spectroscopy; NIRS) were measured. NIRS was also measured during exercise, and rating of perceived exertion (RPE) was recorded after every 10 repetitions. At both speeds, RR displayed greater peak torque, total work, and power output during latter repetitions, but there were no differences between TS or RR when averaging all 40 repetitions. The RPE was less during RR at both speeds (p < 0.05). RR increased select muscle oxygen saturation and blood flow at both speeds. There were no effects of protocol on TMG, but effect sizes favoured a quicker recovery after RR. RR was likely beneficial in maintaining performance compared with the latter parts of TS sets and limiting perceived and peripheral fatigue. Novelty Although effective at slow velocities, rest-redistribution was likely more effective during high-velocity movements in this study. Rest-redistribution maintained the ability to produce force throughout an entire range of motion. Rest-redistribution reduced RPE during both high-velocity and high-force movements.