Continuous Repetitions Research Articles

The PAD-adapted 30-20-10 during Nordic walking: A new exercise training session in patients with symptomatic peripheral artery disease.

This study aimed to investigate the feasibility of a peripheral artery disease (PAD)-adapted 30-20-10 Nordic walking session in patients with symptomatic PAD and to compare the cardiovascular response of this new training session to a traditional walking (TW) and 4 × 4 minutes Nordic walking session. This is a prospective observational study. Patients with Fontaine stage II PAD were included. Patients participated in Nordic walking sessions, which were randomly assigned as TW, 4 × 4 minute intervals, and peripheral artery disease adapted 30-20-10 exercise session (PAD-adapted 30-20-10 sessions). PAD-adapted 30-20-10 and 4 × 4 minutes sessions consisted of 4 repetitions of 4 minutes of effort followed by 3 minutes of passive recovery. PAD-adapted 30-20-10 session was characterized by 4 continuous 1-min repetitions at 3 different walking speeds [high (30 seconds), moderate (20 seconds) and low (10 seconds)]. During the 4 × 4 minutes session, patients were asked to cover the maximal distance at a constant speed. During TW session, patients were asked to walk at a speed inducing moderate-to-severe claudication pain. Heart rate, rating of perceived exertion (RPE) and claudication pain intensity using a visual analog scale were assessed. The perceived enjoyment of each session was assessed using a visual analog scale ranging from 0 (not enjoyable) to 10 (very enjoyable). Eleven patients with chronic symptomatic PAD were included (62 ± 13 years; 54% women). The mean heart rate during the time of effort was significantly higher in PAD-adapted 30-20-10 group than in 4 × 4 minutes and TW groups (127 ± 12, 122 ± 12, 114 ± 11 bpm, respectively; P ≤ .001). The mean rating of perceived exertion (16 ± 1, 15 ± 1, 13 ± 1; P ≤ .001) and claudication pain intensity (8 ± 1, 7 ± 1; 7 ± 1 mm; P ≤ .019) were significantly higher during PAD-adapted 30-20-10 sessions than during 4 × 4 minutes and TW sessions. The perceived enjoyment was similar among sessions (8.7 ± 1.6 for TW, 8.6 ± 1.7 for 4 × 4 minutes, and 8.8 ± 1.8 mm for PAD-adapted 30-20-10 sessions; P = .935). The PAD-adapted 30-20-10 session is feasible and induces higher cardiovascular stimulation and claudication pain than 4 × 4 minutes and TW procedures in patients with symptomatic PAD. Despite these different responses, a similar perceived enjoyment among the sessions has been shown. Future investigations are needed to examine the effects of this new training session in these patients.

Acute Responses to Traditional and Cluster-Set Squat Training With and Without Blood Flow Restriction.

Cornejo-Daza, PJ, Sánchez-Valdepeñas, J, Páez-Maldonado, J, Rodiles-Guerrero, L, Boullosa, D, León-Prados, JA, Wernbom, M, and Pareja-Blanco, F. Acute responses to traditional and cluster-set squat training with and without blood flow restriction. J Strength Cond Res 38(8): 1401-1412, 2024-To compare the acute responses to different set configurations (cluster [CLU] vs. traditional [TRA]) under distinct blood flow conditions (free vs. restricted) in full-squat (SQ). Twenty resistance-trained males performed 4 protocols that differed in the set configuration (TRA: continuous repetitions; vs. CLU: 30 seconds of rest every 2 repetitions) and in the blood flow condition (FF: free-flow; vs. blood flow restriction [BFR]: 50% of arterial occlusion pressure). The relative intensity (60% 1RM), volume (3 sets of 8 repetitions), and resting time (2 minutes) were equated. Mean propulsive force (MPF), velocity (MPV) and power (MPP), and electromyography (EMG) parameters were recorded during each repetition. Tensiomyography (TMG), blood lactate, countermovement jump (CMJ) height, maximal voluntary isometric contraction, in SQ, and movement velocity against the load that elicited a 1 m·s -1 velocity at baseline (V1-load) in SQ were assessed at pre- and post-exercise. The CLU protocols allowed a better maintenance of MPF, MPV, MPP, and EMG median frequency during the exercise compared to TRA (clu-time interaction, p < 0.05). The TRA protocols experienced greater impairments post-exercise in TMG- and EMG-derived variables (clu-time interaction, p < 0.05) and SQ and CMJ performance (clu-time interaction, p = 0.08 and p < 0.05, respectively), as well as higher blood lactate concentrations (clu-time interaction, p < 0.001) than CLU. Moreover, BFR displayed decreases in TMG variables (bfr-time interaction, p < 0.01), but BFR-CLU resulted in the greatest reduction in twitch contraction time ( p < 0.001). Cluster sets reduced fatigue during and after the training session and BFR exacerbated impairments in muscle mechanical properties; however, the combination of both could improve contraction speed after exercise.

Attentional Distractions Do Not Influence Lumbar Spine Local Dynamic Stability during Repetitive Flexion-Extension Movements

The association between low back pain and lumbar spine local dynamic stability (LDS) appears to be modulated by if and how someone catastrophizes about pain, suggesting that the cognitive perceptions of pain may influence an individual’s ability to control lumbar spine motion. Previous work also demonstrates that directing cognitive resources and attentional focus can influence movement performance. Therefore, we aimed to examine whether distracting attentional focus would influence lumbar spine LDS during repetitive flexion-extension movements. Sixteen participants performed repetitive spine flexion-extension movements under two baseline conditions (pre- and post-), and while attentional focus was distracted by either an external sensory stimulus or a cognitive-motor dual-task, both targeted at the hands. Lumbar spine LDS was examined over 30 continuous movement repetitions using maximum Lyapunov exponents. In comparison to both Baseline and Post-Baseline trials, the perceived mental workload was significantly elevated during the cognitive-motor dual-task trial but not the external sensory stimulus trial. The only statistically significant effect on LDS occurred in the Post-Baseline trial, where LDS was higher than in the cognitive-motor dual-task. In combination with previous work, these findings suggest that distracting attentional focus during repetitive lumbar spine flexion-extension movements does not have a negative influence on lumbar spine LDS.

COMBINED HIGH-INTENSITY INTERVAL TRAINING FOR PEOPLE WITH DISORDERS OF GUT BRAIN INTERACTION: A CASE REPORT

AIMS The efficacy of high intensity exercise for improving symptoms of chronic idiopathic constipation, a highly prevalent disorder of gut brain interaction (DGBI), remains uncertain. The aim of this case report was to investigate the feasibility, safety, and efficacy of 8-weeks of combined high-intensity interval training (C-HIIT) for a person (female, 23 years old) with chronic constipation. METHODS The participant enrolled in the C-HIIT for DGBI controlled trial that aims to recruit 32 participants with DGBI. Following comprehensive assessments of gastrointestinal symptoms, neuromuscular fitness, cardiorespiratory fitness and mental health, the participant completed an 8-week intervention consisting of thrice weekly 26-minute C-HIIT sessions. These consisted of a 3-minute aerobic warm-up (treadmill; 50-60% peak heart rate [HRpeak]) followed by 4-minutes of high-intensity aerobic exercise at ≥85% HRpeak. After 1-minute rest, eight whole body resistance exercises were performed. These involved continuous repetitions with good technique for 1-minute at an ≥8/10 (very hard) rating of perceived exertion; 1-minute rest separated each exercise. Adverse events were recorded throughout the intervention. RESULTS The participant adhered to the intervention, attending 100% of sessions and reaching the prescribed intensity for 100% of aerobic and 80% of resistance exercises. Efficacy of the exercise training was indicated by a reduction in the severity of gastrointestinal symptoms measured via the irritable bowel syndrome-symptom severity scale (from 111 to 100) and the structured assessment of gastroIntestinal symptoms (39 to 12). There were some improvements in neuromuscular fitness (handgrip strength: 27 to 29.5 kg, 30-second sit to stands: 12 to 10 repetitions) and cardiorespiratory fitness (VO2max: 36.7 to 38.2 mL/kg/min). No changes were observed in mental health (Hospital Anxiety and Depression scale), and one non-serious adverse event (nausea post-eating), which was deemed not related to the intervention. CONCLUSION The C-HIIT intervention in a person with DGBI was feasible, efficacious and safe.

Metaphorical fields in V. Kaverin’s novel "The two captains" (to the 120th anniversary of the birth)

The paper focuses on the identification and description of text-building and meaning-forming (world-modelling, conceptual) metaphorical fields in V. Kaverin’s novel "The Two Captains". The metaphorical field is viewed as a hierarchical structure. The core zone is comprised of the conceptual metaphor "life/world – creativity"; the centre zone includes metaphors extending the core metaphor, in the first place, the metaphors "book of life/life – book" and "world – theatre" (read life, a page of life, the main character and others). The linguistic units which are used simultaneously in their literal and figurative meanings (history) constitute the periphery zone. The world-modelling metaphor forms a system of "figurative parallels" in the novel. Due to this, the form of a trope can vary though its stable semantic significance remains unchanged. "Figurative" parallels include cover not only tropes, but also words in their literal meaning. Owing to continuous repetitions and associative connections with metaphorical contexts, such words support and expand the sphere of influence of extended metaphors. Life as such is perceived in the novel as creative work harmonizing reality due to the expansion of the metaphor scope with the help of intertextual inclusions (The world is a theatre, people are actors and others) and as a result of the reconceptualization of the metaphors theatre, game. They change their negative connotation ("acting") to positive ("creativity"). The metaphors (book of life –) theatre and (book of life –) fairytale receive the additional meaningful connotations "realisation of a dream, fulfilment of passionate desires". Although the subject and image of the metaphors included in the metaphorical field differ, the seme ‘creativity’ enters the comparison feature of each of them.

TUG-10: A Modification of the Timed Up and Go Test for Aerobic Assessment in Older Adults

Purpose: Cardiorespiratory fitness tests are important for older adults to determine baseline cardiovascular fitness and appropriate aerobic exercise intensity. The Timed Up and Go (TUG) is a test that can be modified to challenge the aerobic system by performing 10 continuous repetitions (TUG-10). The TUG-10 advantages include less space and time requirements and incorporation of functional tasks with balance challenges. The purpose of this study was to relate the performance and physiologic responses of the TUG-10 to other common aerobic capacity tests. Methods: Fourteen independent community-dwelling adults performed the 6-minute-walk test (6MWT), 2-minute-step test (2MST), and TUG-10. Heart rate (HR), diastolic and systolic blood pressure, and rate of perceived exertion (RPE) were recorded before and after each test. Bland–Altman plots were used to determine the agreement between test performances. Repeated measures mixed models compared differences in the physiologic changes between the tests. Results: Participants had a clinically greater increase in the adjusted mean change in HR during the 2MST (22.5 bpm) than the 6MWT (17.0 bpm) and TUG-10 (12.3 bpm). Diastolic blood pressure response was similar across all 3 tests with no significant change. Systolic blood pressure increased less during the 6MWT (15.4 mm Hg) compared with the 2MST (33.3 mm Hg) and TUG-10 (28.7 mm Hg). Participants reported a higher RPE during the 2MST (7.9) than the 6MWT (6.1) and TUG-10 (5.2). The Bland–Altman plots indicated that participants' performance on the 3 tests was comparable. Conclusions: The TUG-10, 6MWT, and 2MST demonstrated comparable performances and clinically similar physiologic changes. Heart rate and RPE changes were greater during the 2MST than the other tests, suggesting that the 2MST was more demanding. Findings support the TUG-10 as a potential functional outcome measure to estimate cardiorespiratory fitness. Moreover, the TUG-10 required minimal space and time and may facilitate the gap in aerobic testing in physical therapy practice.

Quantum consensus dynamics by entangling Maxwell demon

We introduce a Maxwell demon which generates many-body entanglement robustly against bit-flip noises, allowing us to obtain quantum advantage. Adopting the protocol of the voter model used for opinion dynamics approaching consensus, the demon randomly selects a qubit pair and performs a quantum feedback control, in continuous repetitions. We derive upper bounds for the entropy reduction and the work extraction rates by the demon’s operation. These bounds are determined by a competition between the quantum–classical mutual information acquired by the demon and the absolute irreversibility of the feedback control. Our finding of the upper bounds corresponds to a reformulation of the second law of thermodynamics under a class of Maxwell demon which generates many-body entanglement in a working substance. This suggests that a general condition for the operation of a successful entangling demon, one for which many-body entanglement stabilization and work extraction are possible, is that the information gain is larger than the absolute irreversibility.

Speaking clearly improves speech segmentation by statistical learning under optimal listening conditions

This study investigated the effect of speaking style on speech segmentation by statistical learning under optimal and adverse listening conditions. Similar to the intelligibility and memory benefits found in previous studies, enhanced acoustic-phonetic cues of the listener-oriented clear speech could improve speech segmentation by statistical learning compared to conversational speech. Yet, it could not be precluded that hyper-articulated clear speech, reported to have less pervasive coarticulation, would result in worse segmentation than conversational speech. We tested these predictions using an artificial language learning paradigm. Listeners who acquired English before age six were played continuous repetitions of the ‘words’ of an artificial language, spoken either clearly or conversationally and presented either in quiet or in noise at a signal-to-noise ratio of +3 or 0 dB SPL. Next, they recognized the artificial words in a two-alternative forced-choice test. Results supported the prediction that clear speech facilitates segmentation by statistical learning more than conversational speech but only in the quiet listening condition. This suggests that listeners can use clear speech acoustic-phonetic enhancements to guide speech processing dependent on domain-general, signal-independent statistical computations. However, there was no clear speech benefit in noise at either signal-to-noise ratio. We discuss possible mechanisms that could explain these results.

"Re - Vinil" e "Meta Remix"

Seguem duas proposições na mesma submissão, ambas baseadas na remontagem de discos de vinil a partir de recortes em máquina laser. Uma delas é um vídeo que mostra algumas das possibilidades visuais e sonoras da proposta. A segunda é um áudio situado no limite entre assemblagem sonora e música, criado a partir da execução dos discos. Na edição, se procurou um equilíbrio entre o casual e o concatenado, de maneira a estimular o ouvinte a modificar espontaneamente sua escuta na medida em que trechos são repetidos em loop. Como um todo, a proposta explora os contrastes entre o que é visível e o que é audível no projeto. Enquanto é possível um maior controle e planejamento no aspecto visual dos discos recombinados, não há como prever o resultado sonoro.

Stroke Perception and Response amongst Elderly Persons in Benin, City, Nigeria

Theories on health behaviour have recognized perceived risk as an essential factor in the adoption of a healthy lifestyle, however, little is known about stroke risk perception and response to stroke in the elderly population of Nigeria. Ageing being the most important unmodifiable risk factor for stroke, this study aims to determine the predictors of perception of stroke risk and response to stroke in the elderly This was a cross-sectional study, which involved a multi-stage random sampling, recruiting one hundred and sixty individuals 65years and older. The interview was by face to face using a questionnaire to determine, demographics, knowledge of stroke risk, perception of stroke risk and response in the event of a stroke. Multiple logistic regression models were used to analyze predictors of dependent variables Only 32.5% of participants had an accurate perception of stroke risk while 30.6% would consider taking a patient to hospital in the event of a stroke. Increasing age (P=0.001), the female gender (P&lt;0.05), having two or more risk factors for stroke (P=0.001) and attending two or more specialized clinics (P=0.001) were significant predictors of the wrong perception of stroke risk and inappropriate response in the event of a stroke. The elderly are at risk for stroke, but sadly with increasing age and additional risk factors for stroke, the majority have a wrong perception of stroke risk and would respond inappropriately in the event of a stroke. It might be necessary to run stroke campaigns that are targeted and appropriate to the elderly, involving continuous intermittent repetitions.

The Association Between Previous Injury And Two Lower Extremity Functional Tests

Previous injury to the lower extremity may increase an athlete’s risk for future injury. Functional screening is one way to determine if an athlete is at a higher risk of future injury. By assessing athletes’ performance on these tests, there is potential for medical providers to implement intervention strategies to decrease risk of future injury. PURPOSE: To determine the association between previous history of injury and two lesser known lower extremity functional tests, the single-leg hip bridge (SLHB) and the single-leg wall-sit (SLWS). METHODS: Sixty-eight recreationally active (participation in exercise or sports for at least 3 days per week for 30 minutes) individuals completed this cross-sectional study. Each participant completed continuous repetitions of a SLHB until failure and repeated on the contralateral leg, as well as a SLWS test, bilaterally, where they were required to hold a single-leg wall sit position until failure. Simple linear regression models were conducted to assess the association between previous injury and the SLHB score and SLWS time. A Poisson regression model was used to assess the association with previous injury for the right and left leg scores on the SLHB. RESULTS: Seventy participants were screened for this study. Of the 70, 2 were excluded, leaving 68 total participants (21 men, 22.4 ± 5.7 years old, 181.96 ± 6.78 cm, and 78.66 ± 10.60 kg and 47 women, 23.3 ± 1.7 years old, 166.30 ± 9.06 cm, and 66.22 ± 9.99 kg). Twenty-five (37%) participants self-reported a previous injury. There was a statistically significant association between a previous injury and the SLHB for the right leg (Relative Risk (RR) = 0.93; 95% Confidence Interval (CI): 0.76-0.93), but not statistically significant association between previous injury and SLHB for the left leg (RR = 0.98; 95% CI: 0.86-1.05). There was no statistically significant association between the SLWS time on either the right (mean difference = 5.57 seconds; 95% CI: -14.17-3.04) or left (mean difference = 5.68 seconds; 95% CI: -13.37-2.02) with previous injury. CONCLUSION: These findings indicate that previous injury to the lower extremity may not affect SLWS time. The SLHB count could be affected depending on the side the injury was on, but additional research is warranted.

Sagittal And Frontal Plane Joint Moments Of The Sumo Deadlift During Shod And Barefoot Conditions

Sumo style deadlifting has recently become more prevalent. Barefoot-style lifting has also become increasingly popular with claims such as increased force production and improved “grounding” of the foot. However, the biomechanics of sumo deadlifting while barefoot have not been examined. PURPOSE: To examine the effects on the hip, knee, and ankle joint moments during a sumo deadlift when comparing shod and barefoot conditions. METHODS: Ten subjects (27.3±3.5 yrs, 1.74±0.13m, 77.97±17.34kg) with minimum six months of deadlift experience (7.6±4.6 yrs), who were free from lower extremity injury, performed 1 repetition maximum (1RM; 137.7±43.0 kg) testing on day 1. This testing was performed in self-selected footwear. On day 2, a minimum of 72 hours later, subjects lifted 70% of their 1RM during a 3-dimensional analysis. Subjects performed one set of five continuous repetitions of a sumo deadlift in shod and barefoot conditions in randomized order. Five minutes of rest was given between sets. Marker data were collected using Qualisys Track Manager, sampling at 240Hz. Force data were collected using Bertec force plates, sampling at 1200Hz. Raw marker and force data were imported into Visual3D. Marker and force data were filtered using a fourth-order lowpass Butterworth filter at 8Hz. Peak internal sagittal and frontal plane joint moments of the hip, knee, and ankle were calculated during the concentric phase of each repetition. Peak vertical ground reaction force was measured during the concentric phase. RESULTS: No significant differences were detected in peak hip extension moment (p=0.855), hip abduction (p=0.288), knee extension (p=0.607), knee abduction (p=0.926), ankle plantarflexion (p=0.376), ankle eversion (p=0.739), or peak vertical ground reaction force (p=0.558). CONCLUSIONS: There is no evidence to suggest that the barefoot lifting style increases performance capabilities when lifting the same weight as in the shod condition. Additionally, there is no evidence to suggest that there is any increased risk in excess frontal plane joint moments during barefoot lifting. Future research should examine the 1RM capabilities in both shod and barefoot conditions to determine if differences exist during maximal compared to submaximal efforts.

The Pedi-CHAMP Agility Test: Completion Rates For Typically Developing Children Aged 5 To 17yrs

The Comprehensive High-Level Activity Mobility Predictor (CHAMP) was developed to assess the rehabilitation and performance in active military service-members who sustained traumatic injury. A pediatric version of this 4-part agility test (the Pedi-CHAMP) has been adapted for use in children aged 5 to 17 years. The Pedi-CHAMP consists of a) 30sec single limb stance (SLS) on each leg, b) a modified Edgren Side-Step Test (Edgren) consisting of 3 continuous repetitions of side-step movements in each direction over a 4m course c) an L-test (10m forward, 10m side-step in each direction, 10m backwards) and d) the Illinois Agility Test (IAT) triple shuttle run with directional weaving on the second pass. PURPOSE: To assess the completion rate of each portion of the Pedi-CHAMP in typically developing children aged 5 to 17 years. METHODS: With IRB-approval, 1,093 children (574 females, average age 11.0±3.9yrs (range 5.0-17.9yrs) were tested and included for analysis. Each participant was given two attempts to complete each portion of the test. If one attempt was unsuccessful or disqualified based on performance, a third attempt was offered. Participants were grouped by age (rounded down to the nearest year) and sex (male/female). A complete test was noted if the participant was able to follow directions and did not demonstrate any performance deemed to disqualify the trial (missed end line/cone, failed to maintain proper body position during side step, etc.) RESULTS: All participants were able to follow the directions and perform the SLS test. It should be noted, however, that 29% were not able to maintain balance for 30 secs on one or both legs. The SLS rate of completion was higher in girls than boys for children aged 5 to 11 years. The overall completion rates for the modified Edgren and L-test tasks were 93% and 92%, respectively. Similar trends between sexes were seen for both tests, with completion rates improving from 74% (Edgren) and 69% (L-Test) in children aged 5yrs to <90% by 8yrs of age. The Illinois Agility Test (IAT) had an overall completion rate of 99%, with all age-sex groups achieving at least 92% completion. CONCLUSION: The Pedi-CHAMP is a 4-part agility test that can be successfully administered in typically developing children aged 5 to 17yrs.

The Oxidative Contribution Of Eight Repeat Bouts Of High Intensity Interval Training

The oxidative contribution to eight repeat bouts of high intensity interval training John Petrizzo, Michele Aquino, Colin Shaw, Justin St Peter, Erica Koutch, Rebecca Flax, Kerianne Nordland, John Wygand, FACSM, Robert Otto, FACSM, Adelphi University, Garden City, NY 11530. Email: [email protected] Interval training requires bouts of work followed by recovery intervals. The intensity of the work interval impacts the metabolic response of the recovery interval. PURPOSE: The purpose was to determine the oxidative cost of both the work (W) interval and the recovery (R) interval during 8 continuous repetitions of high intensity interval training (HIIT) at a workload equivalent to 100% Max VO2. METHODS: All 20 second work intervals were followed by recovery intervals of 10, 20, 30 and 40 sec at 20% of Max VO2. 14 recreationally active college-age students (age: 21.6±1.1 yrs., height: 171.41±0.5 cm, body mass: 75.0±10.6 kg, max VO2 2.89±.67, 8 ♂) volunteered to participate in a randomized, single-blind crossover design study with a minimum of 4 days between trials. A max VO2 ramp protocol on a Lode Cycle ergometer preceded the HIIT trials and established the max workload. VO2 was obtained by continuous open circuit spirometry. RESULTS: Statistical analysis by ANOVA with repeated measures (∗P<.05) was applied to these data.CONCLUSION: Short recovery intervals of 30 seconds or less provide the greatest oxidative stress during interval training, which may be attributed to insufficient phosphagen resynthesis during recovery.

Flash and grab: deep-diving southern elephant seals trigger anti-predator flashes in bioluminescent prey.

ABSTRACTBioluminescence, which occurs in approximately 80% of the world's mesopelagic fauna, can take the form of a low-intensity continuous glow (e.g. for counter-illumination or signalling) or fast repetitions of brighter anti-predatory flashes. The southern elephant seal (SES) is a major consumer of mesopelagic organisms, in particular the abundant myctophid fish, yet the fine-scale relationship between this predator's foraging behaviour and bioluminescent prey remains poorly understood. We hypothesised that brief, intense light emissions should be closely connected with prey strikes when the seal is targeting bioluminescent prey that reacts by emitting anti-predator flashes. To test this, we developed a biologging device containing a fast-sampling light sensor together with location and movement sensors to measure simultaneously anti-predator bioluminescent emissions and the predator's attack motions with a 20 ms resolution. Tags were deployed on female SES breeding at Kerguelen Islands and Península Valdés, Argentina. In situ light levels in combination with duration of prey capture attempts indicated that seals were targeting a variety of prey types. For some individuals, bioluminescent flashes occurred in a large proportion of prey strikes, with the timing of flashes closely connected with the predator's attack motion, suggestive of anti-predator emissions. Marked differences across individuals and location indicate that SES do exploit bioluminescent organisms but the proportion of these in the diet varies widely with location. The combination of wideband light and acceleration data provides new insight into where and when different prey types are encountered and how effectively they might be captured.

Individual and Combined Effect of Inter-repetition Rest and Elastic Bands on Jumping Potentiation in Resistance-Trained Men.

Nickerson, BS, Williams, TD, Snarr, RL, and Park, K-S. Individual and combined effect of inter-repetition rest and elastic bands on jumping potentiation in resistance-trained men. J Strength Cond Res 33(8): 2087-2093, 2019-The purpose of this study was to determine the individual and combined effects of cluster sets (CS) and elastic bands for jumping potentiation in resistance-trained men. Twelve resistance-trained men (age: 22 ± 3 years) participated in this study. In a random order, participants completed 1 set of 3 repetitions at 85% 1-repetition maximum for the parallel back squat: (a) traditional set with continuous repetitions; (b) continuous repetitions with elastic bands (BANDS); (c) CS with 30 seconds of rest between each repetition (CS30); and (d) CS with 30 seconds of rest between each repetition and elastic bands (CS + BANDS). Vertical jump height (JH) and peak power (PP) were measured before exercise (baseline) and at 1, 4, 7, and 10 minutes after exercise for each condition. Results revealed that PP at 10 minutes was significantly higher than 7 minutes for BANDS (p = 0.035) and that 4 and 7minutes were both significantly higher than baseline for CS + BANDS (p = 0.008 and 0.031, respectively). No other differences were observed. There were medium effect sizes (ESs) for PP with BANDS (ES = 0.58 at 10 minutes), CS30 (ES = 0.53 and 0.64 at 7 and 10 minutes, respectively), and CS + BANDS (ES = 0.64, 0.78, and 0.66 at 4, 7, and 10 minutes, respectively). All remaining ES for JH and PP were trivial to small. Based on the moderate magnitude of effect, BANDS, CS30, and CS + BANDS were effective at potentiating vertical jump power. CS + BANDS is a more practical approach to potentiate vertical jump power when athletes are under strict time restraints.

Analysis of Schmidt hammer rebound test results with repetitive impacts for determining the mechanical characteristics of weathered pyroclastic rock surfaces: a case study along the Isotake coast, Japan

Cliffs located along the Isotake coast, Shimane, Japan, are characterized by the development of indents without rockfalls and by the occurrence of rockfalls without indents—even though these cliffs have the same geology. An analytical method was developed to determine the mechanical properties of the rock surfaces of a coastal cliff. Twenty continuous impact repetitions of a Schmidt hammer were applied normal to the cliff surfaces in each test. The results of the tests (26 with indents and 22 without indents) showed a gradual increase in the rebound value with increasing number of repetitions. A new exponential equation was proposed in this study to describe the features of the weathered surfaces. The changes in the results were well approximated by this equation, and the approximation clearly distinguished between the two types of weathered surfaces, with higher rebound values at the surfaces of the cliffs with indents than at the surface of cliffs without indents. The homogeneity and heterogeneity of the surface and inner body of the cliff rock can also be modelled by the coefficients in this equation.

Effect of different inter-repetition rest intervals across four load intensities on velocity loss and blood lactate concentration during full squat exercise

ABSTRACTThis study aimed to analyze the acute effect of inter-repetition rest (IRR) intervals on mechanical and metabolic response during four resistance exercise protocols (REPs). Thirty resistance-trained men were randomly assigned to: continuous repetitions (CR), 10 s (IRR10) or 20 s (IRR20) inter-repetition rest. The REPs consisted of 3 sets of 6, 5, 4 and 3 repetitions against 60, 70, 75 and 80% 1RM, respectively, in the full squat exercise. Muscle fatigue was assessed using: percentage of velocity loss over three sets, percentage of velocity loss against the ~1 m·s−1 load (V1 m·s−1), and loss of countermovement jump (CMJ) height pre-post exercise. Blood lactate was measured before and after exercise. The percentage of velocity loss over three sets and lactate concentration were significantly lower (P < 0.05) for IRR groups compared to CR in all REPs. The CR group showed a significantly higher (P < 0.05) velocity loss against V1 m·s−1 load and loss of CMJ height pre-post exercise than IRR groups in REP against 60% 1RM. In conclusion, both IRR groups produced a significant lower degree of fatigue compared to CR group. However, no significant differences were found in any measured variables between IRR configurations.

Influence of a Cluster Set Configuration on the Adaptations to Short-Term Power Training.

Morales-Artacho, AJ, Padial, P, García-Ramos, A, Pérez-Castilla, A, and Feriche, B. Influence of a cluster set configuration on the adaptations to short-term power training. J Strength Cond Res 32(4): 930-937, 2018-This study investigated the effects of a traditional (TT) vs. cluster (CT) resistance training on the lower-body force, velocity, and power output. Nineteen males were allocated to a CT or a TT group and took part of a 3-week resistance training (2 weekly sessions). CT involved 6 sets of 3 × 2 repetitions (30 seconds rest every 2 repetitions and 4 minutes 30 seconds between sets). TT comprised 6 sets of 6 continuous repetitions (5 minutes rest between sets). Before and after the training period, force (F25, F50, F75), velocity (V25, V50, V75), and power (P25, P50, P75) were obtained during the countermovement jump (CMJ) exercise at 3 external loading conditions (25, 50, and 75% of body mass). Individual linear regressions were used to determine the force-velocity profile including the Slope, estimated maximal theoretical force (F0), velocity (V0), and power (P0). After CT, very-likely moderate increments in P25 were observed compared with TT (p = 0.011, ES = 0.55) because of a very-likely moderate rise in V25 (p = 0.001, ES = 0.71). No significant differences were observed in any of the F-v profile variables between the TT and CT groups (p ≥ 0.207, ES ≤ 0.31). Our results suggest that 3 weeks of muscle power training including cluster set configurations are more efficient at inducing velocity and power adaptations specific to the training load.

Sprayed superamphiphilic copper foams for long term recoverable oil-water separation

Superamphiphilic copper foams were prepared by one-step spraying a water-borne solution of hydroxyl-functionalized multi-wall carbon nanotubes and melamine formaldehyde. Water or oil droplets can spread on the coating rapidly and completely in air; meanwhile, oil droplets underwater can retain quasi-spheres without any penetration all the time (superoleophobic underwater), and so the water droplets underoil can do (superhydrophobic underoil). The superamphiphilic copper foams which prewetted by water can effectively separate oil and water solely driven by gravity, showing high separation efficiency and water flux (>5000Lm−2h−1) for a series of oil-water mixtures. Furthermore, the as-prepared copper foams exhibited outstanding mechanical durability in the long-term mechanical wear process and excellent chemical stability under a series of harsh environment conditions, including strong acid and strong base. Meanwhile, The samples still retained the underwater superoleophobic property after 4 separation-water backwash cycles (>140 continuous separation repetitions) with the separation efficiency always remaining above 95%, which indicated the excellent recoverability and recyclability.