Evaluation methods and objectives for neuromuscular and hemodynamic responses subsequent to different rest intervals in resistance training: a systematic review

Introduction: The training routine planned, and performed correctly results in exercises that, systematically organized, influence the levels of strength, and muscle hypertrophy. However, the magnitudes of these gains vary considerably. To optimize these gains, it is important to underst, and the interaction between training variables such as external load, volume, number of exercises, number of repetitions, duration of repetitions, the order of exercises, number of series, recovery interval between series, and the exercises, as well as the time under tension. The influence of the recovery interval on the response following exercise on neuromuscular components is very important. However, different objectives, and instruments are used to evaluate these responses. Objective: The purpose of this study is to conduct a systematic review of the assessment methods, and objectives for responses after different recovery intervals in strength training. METHODS: The present study is characterized by a systematic review study. Articles found in the following databases were considered for the systematic review: Scopus, PubMed / MEDLINE, Web of Science, Cochrane Library. The following descriptors, and their respective synonyms according to the terms MeSH were used in the databases, both singular, and plural: “Resistance Training”, “Rest Interval”, and “Bech Press”. As filters were used: a) species (humans), and type of study (original). Results: Seven studies were analyzed that met the established criteria. Conclusion: The studies presented have verified the influence of different recovery intervals on muscle, and hemodynamic responses. Evaluating image measurements such as ultrasound, and resonance, blood measurements such as GH, Testosterone, IGF-1, and Lactate, number of repetitions for performance, and fatigue, as well as heart rate, and blood pressure.

Repolarization characteristics indicate electrical instability in ventricular arrhythmia originating from papillary muscle

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): DZHK (German Center for Cardiovascular Research) Introduction Cardiac arrhythmia originating from the papillary muscle can trigger ventricular fibrillation and cause sudden cardiac death even in the absence of structural heart disease. Yet, no clinical parameters are known to reflect the propensity of arrhythmia to degenerate into ventricular fibrillation. Purpose We aimed at identification of parameters associated with degeneration of ventricular arrhythmia into ventricular fibrillation. Methods Ventricular arrhythmia was induced by aconitine injection into the papillary muscle of healthy sheep (n = 12) in an open-chest model. Endocardial high-density-mapping and epicardial mapping were performed. We determined repolarization time and activation-recovery-interval according to the Wyatt method. Results During focal arrhythmia faster conduction occurred in longitudinal and basal direction than transversal and apical direction. The electrical restitution curve, modelling relation of diastolic interval and activation-recovery-interval, is steeper in aconitine-induced ventricular arrhythmia than in ventricular pacing or sinus rhythm. Steeper restitution curves reflect electrical instability and propensity to degenerate into ventricular fibrillation. The repolarization-related parameters activation-recovery interval and repolarization time exhibit higher heterogeneity per beat in ventricular arrhythmia preceding degeneration into ventricular fibrillation. Repolarization time in relation to cycle length (RT/CL), which can easily be measured during electrophysiological procedures, differentiates self-limiting from degenerating arrhythmia with high specificity and sensitivity. Conclusion In structurally normal ovine hearts, the ratio of repolarization and cycle length (RT/CL) in ventricular arrhythmia and greater dispersion of repolarization are indicators of subsequent degeneration into ventricular fibrillation. While dispersion of repolarization is not easily acquired in clinical routine, a simple index (RT/CL) may be sufficient to differentiate between self-limiting and electrically instable arrhythmia with propensity to degenerate to ventricular fibrillation. Abstract Figure. Repolarization in VA model

The acute physiological and perceptual effects of recovery interval intensity during cycling-based high-intensity interval training

Purpose The current study sought to investigate the role of recovery intensity on the physiological and perceptual responses during cycling-based aerobic high-intensity interval training. Methods Fourteen well-trained cyclists ($$\dot{V}{\text{O}}_{{{\text{2peak}}}}$$ V ˙ O 2peak : 62 ± 9 mL kg−1 min−1) completed seven laboratory visits. At visit 1, the participants’ peak oxygen consumption ($$\dot{V}{\text{O}}_{{{\text{2peak}}}}$$ V ˙ O 2peak ) and lactate thresholds were determined. At visits 2–7, participants completed either a 6 × 4 min or 3 × 8 min high-intensity interval training (HIIT) protocol with one of three recovery intensity prescriptions: passive (PA) recovery, active recovery at 80% of lactate threshold (80A) or active recovery at 110% of lactate threshold (110A). Results The time spent at > 80%, > 90% and > 95% of maximal minute power during the work intervals was significantly increased with PA recovery, when compared to both 80A and 110A, during both HIIT protocols (all P ≤ 0.001). However, recovery intensity had no effect on the time spent at > 90% $$\dot{V}{\text{O}}_{{{\text{2peak}}}}$$ V ˙ O 2peak (P = 0.11) or > 95% $$\dot{V}{\text{O}}_{{{\text{2peak}}}}$$ V ˙ O 2peak (P = 0.50) during the work intervals of both HIIT protocols. Session RPE was significantly higher following the 110A recovery, when compared to the PA and 80A recovery during both HIIT protocols (P < 0.001). Conclusion Passive recovery facilitates a higher work interval PO and similar internal stress for a lower sRPE when compared to active recovery and therefore may be the efficacious recovery intensity prescription.

The Acute Physiological and Perceptual Effects of Individualizing the Recovery Interval Duration Based Upon the Resolution of Muscle Oxygen Consumption During Cycling Exercise

Purpose: There has been paucity in research investigating the individualization of recovery interval duration during cycling-based high-intensity interval training (HIIT). The main aim of the study was to investigate whether individualizing the duration of the recovery interval based upon the resolution of muscle oxygen consumption would improve the performance during work intervals and the acute physiological response of the HIIT session, when compared with a standardized (2:1 work recovery ratio) approach. Methods: A total of 16 well-trained cyclists (maximal oxygen consumption: 60 [7] mL·kg−1·min−1) completed 6 laboratory visits: (Visit 1) incremental exercise test, (Visit 2) determination of the individualized (IND) recovery duration, using the individuals’ muscle oxygen consumption recovery duration to baseline from a 4- and 8-minute work interval, (Visits 3–6) participants completed a 6 × 4- and a 3 × 8-minute HIIT session twice, using the IND and standardized recovery intervals. Results: Recovery duration had no effect on the percentage of the work intervals spent at >90% and >95% of maximal oxygen consumption, maximal minute power output, and maximal heart rate, during the 6 × 4- and 3 × 8-minute HIIT sessions. Recovery duration had no effect on mean work interval power output, heart rate, oxygen consumption, blood lactate, and rating of perceived exertion. There were no differences in reported session RPE between recovery durations for the 6 × 4- and 3 × 8-minute HIIT sessions. Conclusion: Individualizing HIIT recovery duration based upon the resolution of muscle oxygen consumption to baseline levels does not improve the performance of the work intervals or the acute physiological response of the HIIT session, when compared with standardized recovery duration.

Long duration of ecological recovery from the early Toarcian extinction event in the Cleveland Basin, North Yorkshire, UK

The Toarcian Oceanic Anoxic Event and associated early Toarcian mass extinction event (ETME) have attracted a great deal of research effort, focusing primarily on the causal mechanisms. In contrast, there is less known of the patterns of biotic recovery following this mass extinction (and others). Yet such recoveries are of interest as they record how surviving organisms radiate into newly vacated ecospace. The Cleveland Basin, North Yorkshire, has one of the most expanded Toarcian rock sections globally. Previous studies have presented a limited view of the recovery interval as the upper Toarcian sequence across much of the basin was truncated by a period of erosion during the Middle Jurassic. However, the Ravenscar coastal section preserves all of the upper Toarcian stratigraphy. In the summers of 2013 and 2017 JWA and CTSL collected 24,002 macrofossil specimens from 37 sample points covering 45 metres of the Ravenscar section, from the top of the Alum Shale Member of the Whitby Mudstone Formation to the top of the Blea Wyke Sandstone Formation. The samples included benthic taxa (principally bivalves and gastropods, with smaller number of brachiopods, echinoderms, serpulids, scaphopods, crustaceans and bryozoans) and nektic taxa (belemnites and ammonites). These allowed us to construct new range data, and allowed us a full evaluation of the biotic recovery from the ETME. Ecological tiering was the first to respond to the amelioration of conditions in the Bifrons Zone, approximately 1.75-2.71 million years following the extinction event. Many of the ecological groups that disappeared across the extinction interval began to reappear, although often represented by only a single species. Benthic species richness and ecological diversity subsequently dropped in the Variabilis and Thoarsense Zones, and then both increased substantially in the Levesquei Zone, coincident with the onset of sandy facies deposition in the basin, 5.1-6.89 million years after the extinction event. It was only then that species and ecological diversity regained their pre-extinction late Pliensbachian to Tenuicostatum Zone values. This surprisingly protracted recovery interval may have been caused by persistent environmental stress and/or sea-level change. Some of the benthic taxa appearing in the late Toarcian Levesquei Zone into the Cleveland Basin are typical of Middle Jurassic faunas. Future work will be to ascertain from where these immigrants came. This will present taxonomic challenges that require whole-community collaboration.

Long duration of ecological recovery from the early Toarcian extinction event in the Cleveland Basin, North Yorkshire, UK

The Toarcian Oceanic Anoxic Event and associated early Toarcian mass extinction event (ETME) have attracted a great deal of research effort, focusing primarily on the causal mechanisms. In contrast, there is less known of the patterns of biotic recovery following this mass extinction (and others). Yet such recoveries are of interest as they record how surviving organisms radiate into newly vacated ecospace. The Cleveland Basin, North Yorkshire, has one of the most expanded Toarcian rock sections globally. Previous studies have presented a limited view of the recovery interval as the upper Toarcian sequence across much of the basin was truncated by a period of erosion during the Middle Jurassic. However, the Ravenscar coastal section preserves all of the upper Toarcian stratigraphy. In the summers of 2013 and 2017 JWA and CTSL collected 24,002 macrofossil specimens from 37 sample points covering 45 metres of the Ravenscar section, from the top of the Alum Shale Member of the Whitby Mudstone Formation to the top of the Blea Wyke Sandstone Formation. The samples included benthic taxa (principally bivalves and gastropods, with smaller number of brachiopods, echinoderms, serpulids, scaphopods, crustaceans and bryozoans) and nektic taxa (belemnites and ammonites). These allowed us to construct new range data, and allowed us a full evaluation of the biotic recovery from the ETME. Ecological tiering was the first to respond to the amelioration of conditions in the Bifrons Zone, approximately 1.75-2.71 million years following the extinction event. Many of the ecological groups that disappeared across the extinction interval began to reappear, although often represented by only a single species. Benthic species richness and ecological diversity subsequently dropped in the Variabilis and Thoarsense Zones, and then both increased substantially in the Levesquei Zone, coincident with the onset of sandy facies deposition in the basin, 5.1-6.89 million years after the extinction event. It was only then that species and ecological diversity regained their pre-extinction late Pliensbachian to Tenuicostatum Zone values. This surprisingly protracted recovery interval may have been caused by persistent environmental stress and/or sea-level change. Some of the benthic taxa appearing in the late Toarcian Levesquei Zone into the Cleveland Basin are typical of Middle Jurassic faunas. Future work will be to ascertain from where these immigrants came. This will present taxonomic challenges that require whole-community collaboration.

Feasibility of Aerobic Interval Training in Nonambulant Persons after Stroke

ABSTRACT Background: Modifiable cardiovascular risk factors are prevalent and poorly managed in people after stroke. Aerobic exercise is effective in reducing many modifiable cardiovascular risk factors after stroke but is challenging and under-researched in nonambulant persons. This pilot study aimed to investigate the feasibility of aerobic interval training in nonambulant persons after stroke. Methods: Aerobic exercise was performed on an upright or semi-recumbent cycle ergometer. Participants were prescribed 4 × 4-min intervals of exercise at 85% maximum age-predicted heart rate (APHRmax) with a 3-min active recovery at 70%APHRmax per 30-min session, 3 times per week for 10 weeks. Heart rate, rating of perceived exertion, workload, cadence, and duration of exercise achieved were recorded for each interval. Results: Nine participants (mean ± SD; age 62 ± 12 y; 5 males) unable to walk without assistance after stroke (2.9 ± 3.9 y) were recruited. There were no adverse events reported, but there was one dropout (due to bronchitis). Attendance for the remaining participants was 93 ± 6%. The mean training %APHRmax was 72 ± 14% for the higher intensity interval and 57 ± 21% for the recovery interval. The mean increase in training workload between weeks 1 and 10 was 11.2 ± 11.6 W (27 ± 28%) for the higher intensity interval and 4.0 ± 7.7W (17 ± 33%) for the recovery interval. The mean increase in VO2peak was 2.3 ± 2.9 mL·kg−1·min−1 (18 ± 22%) over the 10-week intervention. Conclusion: Aerobic interval training at a moderate-vigorous intensity on an upright or recumbent cycle ergometer is feasible for nonambulant persons after stroke. Aerobic interval training should be further investigated to determine its potential to improve cardiorespiratory fitness after stroke and risk factors for recurrent stroke.