Exercise Pacing Research Articles

ПРИМЕНЕНИЕ ПРИНЦИПОВ ДОПОЛНИТЕЛЬНОЙ НАГРУЗКИ В ПРОЦЕССЕ ВЫПОЛНЕНИЯ СТУДЕНТАМИ СИЛОВЫХ УПРАЖНЕНИЙ

The reserves for improving the effectiveness of strength exercises are systematized, based on the use by students of methodological principles of additional load: the pace of exercise, load dosing, the principle of a triple set, contributing to the improvement of muscle mass, strengthening muscles and connective tissue

Empowering Recovery: Knowledge, Attitude, and Experience among the Physiotherapy Fraternity for Long COVID Rehabilitation: A Cross-sectional Study

Background: Physiotherapy plays a crucial role in the rehabilitation of long COVID. Objectives: This study aimed to assess the knowledge, attitudes, and experiences of the physiotherapy community in the United Arab Emirates (UAE) regarding the management of long-term COVID-19. Methods: Conducted as a cross-sectional study utilizing convenient sampling through an online survey, it involved physiotherapists and physiotherapy students throughout the United Arab Emirates, achieving a response rate of 434 (93.13%). Results: Fatigue (76%) and shortness of breath (56.2%) were the most commonly reported symptoms, with the Generic PROMIS (51.6%) and Post-COVID-19 Functional Status Scale (41.7%) being the most utilized outcome tools. Sixty-eight percent of participants felt confident in differentiating between COVID-19 complications and long COVID symptoms, whereas 18.7% were unsure, and 13% admitted difficulty in differentiation. The approaches reported for managing long COVID included graded exercise, symptom-titrated physical activity, and pacing exercise principles (63.21%, 37.79%, and 31.8%, respectively), alongside exercise capacity tests like the 1-minute sit-to-stand and 10MWT (71.9%) for screening and recommending physical activity. A significant majority (87.3%) expressed a desire for more information on long COVID rehabilitation, and 87.8% showed interest in specialized training. However, gaps were identified in screening and prescribing exercise or physical activity for long-term COVID-19 rehabilitation. Conclusions: There is a need for regular updates on long-term COVID science and education, emphasizing the spectrum of long-term COVID symptoms versus emerging complications, and skill training in advanced respiratory physiotherapy care or exercise training specifically for long-term COVID. This will aid in integrating recent clinical practice guidelines more effectively.

Exercise-induced downregulation of serum interleukin-6 and tumor necrosis factor-alpha in Egyptian handball players.

Muscles of candidates work at various grades of intensity during handball exercises according to the pace of exercise. The movement pattern involves large number of contractions, feints, dodges and numerous changes in movements, all of which are highly responsible for changes in trainer's organs, including the immune system. In this study, inflammatory mediators involving interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) in serum of 18 Egyptian male handball players, selected from Tanta club handball under 21 year’s old team, were analyzed. The analysis was established on samples collected just before and immediately after intermediate reasonable exercise via enzyme linked immunosorbent assay (ELISA). Moreover, white blood cells (WBCs) count and other hematological markers including hemoglobin %, hematocrit value, and platelet count were assessed. Our results demonstrated a significant decrease in the levels of IL-6 and TNF-α after exercise compared to those before exercise. This was coupled with an increase in WBCs and platelets count. It is also noteworthy that there was a significant positive correlation between serum levels of IL-6 and TNF-α in the study subjects coupled with a significant negative correlation between IL-6 and WBCs after the exercise. Therefore, it is concluded that intermediate reasonable exercises result in decreased levels of IL-6 and TNF-α, which result in decreasing of the inflammation and help in healing and rapid recovery of muscles of the candidates.

Особливості формування біохімічних механізмів енергозабезпечення у процесі розвитку витривалості спортсменок у спортивній аеробіці

Galyna Artemyeva & Maryna Khorkova The duration of the competitive program in sports aerobics is about 1.5 minutes, during which the athlete must perform high-intensity complex coordination movements that are combined with acrobatic elements. The implementation of these exercises is necessarily subject to musical accompaniment, which sets the pace of exercise. With the athlete advanced training, the competitive program acquires changes and is saturated with more complex elements. In this regard, the trainers are constantly faced with the task of selecting exercises that would be able to solve the problem of developing the optimal level of endurance, which will allow more technically complete the given exercises. Since sports aerobics is a young sport that is gaining its development, today the basis for many years of training athletes has not yet been formed theoretically. The issues of developing endurance also remain uncertain, and it does not allow coaches to more fully build the training process of their pupils. Purpose: to find out the features of the formation of biochemical mechanisms of energy supply in the process of endurance development female athletes in sports aerobics. Materials & Methods: the study was organized on the basis of the municipal out-of-school educational institution Center for Children and Youth Creativity Dream of the city of Kryvyi Rig, which was attended by 10 female athletes 14–15 years old, at the stage of basic sports training. In the process of the experiment, the following methods were used: theoretical analysis and generalization of scientific and methodological literature; study of documentary materials, video materials of competitions, pedagogical observation, pedagogical testing, methods of mathematical statistics. Results: presented results of a study of the features of the formation of biochemical mechanisms of energy supply in the process of development of endurance athletes in sports aerobics. Experimental data indicate that in the process of developing endurance of athletes in sports aerobics, the efficiency of the glycolytic mechanism of ATP resistance increased, and a positive effect of the proposed funds on the adaptation processes in the test organism during the transition from creatine-phosphate mechanism of energy supply to glycolytic was revealed. Conclusions: compositions in sports aerobics are marked by the complex coordination nature of the exercises, which must also be performed with great intensity and high pace throughout the competition program. Therefore, the development of such a physical quality as endurance is very important for athletes of this sport. The duration of the competitive program in sports aerobics determines the formation of the leading mechanisms of energy supply in the process of endurance development, namely: the efficiency of the glycolytic mechanism of ATP resistance, as well as adaptation processes in the body of athletes during the transition from creatine phosphate to glycolytic mechanisms, increase.

Investigation of Complexity and Regulatory Role of Physiological Activities During a Pacing Exercise

Existing physiological control fatigue models propose that there may be a regulator in the central nervous system which modulates our daily physical activity. Within limits, this regulator ensures physical activity is completed without physiological system failure through interactive communications between the peripheral systems and the central systems. The ability of the central nervous system to regulate exercise is vital to optimise sport performance when severe intensity exercise might be required for prolonged or frequent periods. Based on mathematical models, this investigation explores the complex relationship between some of the mechanisms controlling physical activity and behaviour. In order to analyse the system control mechanisms, heart rate, volume of oxygen consumption and power output were measured for a well-trained male cyclist. Using power spectrum analysis, fractal analysis and continuous wavelet transforms, we show that the system control mechanisms regulating physiological systems, have distinct complexity. Moreover, the potential central controller uses specific frequency bands simultaneously to control and communicate with the various physiological systems. We show that pacing trials are regulated by different physiological systems.

Centre of Mass Acceleration-Derived Variables Detects Differences between Runners of Different Abilities and Fatigue-Related Changes during a Long Distance Over ground Run

Background: Wireless accelerometers provide a method of performing running assessments in sports-specific environments. The purpose of this study was to investigate differences in running movement using centre of mass acceleration-derived variables between runners of varying skill levels and examine fatigue-related changes during a long distance over ground run. Methods: Ninety-two runners performed a self-selected paced long distance over ground run, with a tri-axial accelerometer attached to their low back. Runners were divided into four groups (elite, advanced, intermediate and slow) based on their finishing run time. Spatiotemporal (contact time, flight time, step frequency), dynamic postural stability (ratio of root mean square of accelerations), dynamic loading (peak impact and braking accelerations) and variability (step and stride regularity), were derived from acceleration data. Speed and acceleration-derived variables were used to investigate between group differences and within group fatigue-related changes. Results: Faster runners (elite and advanced groups) exhibited significantly shorter contact times and higher step frequencies than the slow group. Fatigue-related changes throughout the run were only observed amongst the slower runners (intermediate and slow groups). The main changes in the intermediate group were an increase in ratio of root mean square in mediolateral acceleration, and a decrease in speed in the slow group. Conclusion: The shorter contact times and higher step frequencies and no fatigue-related changes exhibited by the faster runners indicate an efficient running movement pattern. Fatigue-related changes in the slower runners were a decrease in postural dynamic stability in mediolateral direction in the intermediate group and a decrease in speed in the slow group which impacted on performance. These runners would benefit from exercise interventions and pacing strategies to reduce these fatigue-related changes and improve performance.

Dopaminergic Genetic Variants and Voluntary Externally Paced Exercise Behavior

Most candidate gene studies on the neurobiology of voluntary exercise behavior have focused on the dopaminergic signaling pathway and its role in the mesolimbic reward system. We hypothesized that dopaminergic candidate genes may influence exercise behavior through additional effects on executive functioning and that these effects are only detected when the types of exercise activity are taken into account. Data on voluntary exercise behavior and at least one single-nucleotide polymorphism/variable number of tandem repeat (VNTR) were available for 12,929 participants of the Netherlands Twin Registry. Exercise activity was classified as externally paced if a high level of executive function skill was required. The total volume of voluntary exercise (minutes per week) as well as the volume specifically spent on externally paced activities were tested for association with nine functional dopaminergic polymorphisms (DRD1: rs265981, DRD2/ANKK1: rs1800497, DRD3: rs6280, DRD4: VNTR 48 bp, DRD5: VNTR 130-166 bp, DBH: rs2519152, DAT1: VNTR 40 bp, COMT: rs4680, MAOA: VNTR 30 bp), a polygenic score (PGS) based on nine alleles leading to lower dopamine responsiveness, and a PGS based on three alleles associated with both higher reward sensitivity and better executive functioning (DRD2/ANKK1: "G" allele, COMT: Met allele, DAT1: 440-bp allele). No association with total exercise volume or externally paced exercise volume was found for individual alleles or the nine-allele PGS. The volume of externally paced exercise behavior was significantly associated with the reward and executive function congruent PGS. This association was driven by the DAT1 440-bp and COMT Met allele, which acted as increaser alleles for externally paced exercise behavior. Taking into account the types of exercise activity may increase the success of identifying genetic variants and unraveling the neurobiology of voluntary exercise behavior.

Exercise Intensity and Pacing Strategy of Cross-country Skiers during a 10 km Skating Simulated Race

The aim of this study was to observe the cardiovascular demands by monitoring the heart rate (HR) and the pacing strategy by evaluating the speed during a simulated cross-country skiing race. Eleven skiers (16.45 ± 1.67 yrs; 21.32 ± 2.03 kg m–2; 72.35 ± 4.69 mL min–1 kg–1) competed in a 10km event divided into four laps. The HR profile was classified into four intensity zones. The skiers spent 66.84 ± 23.64% and 31.82 ± 23.77% of the total time above 90% and at 80 – 90% of the HRmax respectively, whereas the lower zones were negligible. During the event, a progressive increase in intensity was observed: HRmean raised by 2.42% in the last versus the first lap (p < 0.001). The skiers decreased their speed in the second (p = 0.017) and the third laps (p < 0.001) compared to with the first lap. In the fourth lap the skiers increased the speed slightly but without statistical difference. The speed maintained by the skiers resulted in the adoption of a reverse J-shaped pacing strategy.

Early change in thermal perception is not a driver of anticipatory exercise pacing in the heat

AimInitial power output declines significantly during exercise in hot conditions on attaining a rapid increase in skin temperature when exercise commences. It is unclear whether this initial reduced power is...

Volume-Dependent Response of Precooling for Intermittent-Sprint Exercise in the Heat

This study aimed to assess the effects of precooling volume on neuromuscular function and performance in free-paced intermittent-sprint exercise in the heat. Ten male, team-sport athletes completed four randomized trials involving an 85-min free-paced intermittent-sprint exercise protocol in 33°C ± 33% relative humidity. Precooling sessions included whole body (WB), head + hand (HH), head (H), and no cooling (CONT) applied for 20 min before exercise and 5 min during exercise. Maximal voluntary contractions were assessed before and after intervention and during and after exercise. Exercise performance was assessed with sprint times, percent decline and distances covered during free-paced bouts. Measures of core (Tc) and skin (Tsk) temperatures, HR, perceptual exertion, and thermal stress were monitored throughout. Venous and capillary blood samples were analyzed for metabolite, muscle damage, and inflammatory markers. WB precooling facilitated the maintenance of sprint times during the exercise protocol with reduced percent decline (P = 0.04). Mean and total hard running distances increased with precooling 12% compared with CONT (P < 0.05); specifically, WB was 6%-7% greater than HH (P = 0.02) and H (P = 0.001), respectively. No change was evident in mean voluntary or evoked force before to after exercise with WB and HH cooling (P > 0.05). WB and HH cooling reduced Tc by 0.1°C-0.3°C compared with other conditions (P < 0.05). WB Tsk was suppressed for the entire session (P = 0.001). HR responses after WB cooling were reduced (P = 0.05; d = 1.07) compared with CONT conditions during exercise. A relationship between precooling volume and exercise performance seems apparent, as larger surface area coverage augmented subsequent free-paced exercise capacity, in conjunction with greater suppression of physiological load. Maintenance of maximal voluntary contraction with precooling despite increased work output suggests the role of centrally mediated mechanisms in exercise pacing regulation and subsequent performance.

The Effects of Dietary Nitrate Supplementation on Time Trial Performance in Trained Cyclists

Supplementation with nitrate-rich beetroot juice (BR) has been reported to lower resting blood pressure, reduce the oxygen cost (VO2) of exercise and extend time to exhaustion during high-intensity steady state exercise (Bailey et al. J Appl Physiol 107: 1144-55). However, no study to date has investigated the effects of nitrate supplementation on self-paced exercise performance. PURPOSE: To determine the effects of BR supplementation on 16 km time trial performance in trained cyclists. METHODS: Eight male cyclists completed an exercise test to determine their ventilatory threshold (VT) before receiving either 500 ml·day-1 of BR or 500 ml·day-1 of placebo (PL: blackcurrant cordial and water) for six consecutive days in a single-blind, randomised cross-over design. Subsequently, each participant completed 30 min of steady state cycling at 80% VT followed immediately by a 16 km time trial. Respiratory variables, heart rate, blood [lactate] and [glucose] were collected at 5 min intervals during the steady state exercise. RESULTS: There were no differences in heart rate (p=0.19), [lactate] (p=0.21) or [glucose] (p=0.28) between conditions. VO2 was significantly lower during the steady state exercise in the BR condition (2.2 ± 0.2 L/min) compared to the PL condition (2.4 ± 0.2 L/min, p=0.04). The time to complete the 16 km time trial was not different between experimental conditions (BR: 26.1 ± 2.2 min vs. PL: 25.8 ± 1.9 min, p=0.34). CONCLUSIONS: Consistent with previous research, dietary nitrate supplementation in the form of BR resulted in a significant reduction in VO2 during steady state exercise. However, BR did not enhance self paced exercise performance in trained cyclists. Further research is required to identify the physiological mechanism underlying the action of dietary nitrate supplementation on exercise performance.

Effect of Stroke Rate Reduction on Swimming Technique During Paced Exercise

The purpose of this study is to analyze the acute adaptations of motor organization subsequent to a reduction in spontaneous stroke rate (SR) at different swimming speeds, a task constraint that is currently used by trainers to improve stroke technique. Ten well-trained swimmers (8 males and 2 females, whose mean swimming speed on a 400-m front crawl stroke represents 76.8 ± 3.7% and 73.3 ± 2.7% of the mean speed of the short-course pool world record, respectively) performed 3 sets of 3 time to exhaustion trials in front crawl at paces corresponding to 95%, 100%, and 110% of the mean speed measured in a 400-m race. During the first set, individual SR was continuously recorded and averaged. During the second set (Fixed), participants were constrained to swim at their individual corresponding SR. For the third set (Lowered), an individual corresponding SR value lowered by 5% was imposed. Durations of trials and arm stroke phases durations were analyzed. The results showed that the durations of the whole trials declined significantly from the Fixed set to the Lowered set (p < 0.05). Swimmers spent more time in the nonpropulsive phases (increases ranged from 8.6-13.2%; p < 0.05), and the duration of the propulsive phases did not differ significantly in the lowered set. The significant decline in exercise durations might have been caused by an unusual muscular solicitation. Swimming technique changes during trials in the Fixed set suggest an increase in magnitude and efficiency in the propulsive force and a better body streamlining to limit an increase of the resistive impulse in between arm propelling actions. In conclusion, these results should be taken into account to better define training-set technical benefits and better include the impact of such task constraints into the training schedule.

Self-paced exercise is less physically challenging than enforced constant pace exercise of the same intensity: influence of complex central metabolic control

Objective: To examine whether self-pacing reduces the physiological challenge of performing 5000 m rowing ergometry exercise in comparison with a matched-intensity exercise condition in which a constant effort pacing strategy...

Changes in swimming technique during time to exhaustion at freely chosen and controlled stroke rates

The aim of this study was to assess technical changes during constrained swimming in time-to-exhaustion tests. Ten swimmers of national standard performed a maximal 400-m front crawl and two sets of exhaustion tests at 95%, 100%, and 110% of mean 400-m speed. In the first set (free), swimmers had to maintain their speeds until exhaustion and mean stroke rate was recorded for each test. In the second set (controlled), the same speed and individual corresponding stroke rate were imposed. The durations of the exhaustion tests, relative durations of the stroke phases, and arm coordination were analysed. For each speed in the “controlled” set, the exhaustion tests were shorter. Moreover, variables were consistent, suggesting a stabilization of stroke technique. Under the free condition, stroke rate increased to compensate for the decrease in stroke length. At the same time, swimmers reduced the relative duration of their non-propulsive phases in favour of the propulsive phases. Thus, swimmers changed their arm coordination, which came close to an opposition mode. These two constraints enable swimmers both to maintain their stroking characteristics and develop compensatory mechanisms to maintain speed. Moreover, stroke rate can be seen as a useful tool for controlling arm technique during paced exercise.

Fitness Versus Fatness: the Debate Continues

To the Editor: We read with interest the articles about the effect of exercise training on C-reactive protein (CRP) levels1,2 and the accompanying editorial.3 Okita et al1 showed that a 2-month period of exercise training in women with a wide range (20.4 to 39.0) of body mass index (BMI) reduced CRP concentrations independently of the magnitude of weight loss. Obisesan et al2 reported that gene variants of CRP are not related to reduction of CRP levels induced by exercise training (24 weeks) in 63 sedentary men and women (prevalence of obesity not specified). Surprisingly enough, weight reduction was greater in the first study (3 kg on average) than in the second study (range of weight loss 1.1 to 1.8 kg). In none of the two studies was there any statement about the cut of daily calories at the end of the observation. This seems particularly strange as losing weight with exercise alone is more difficult because of the accompanying increase in free fat mass (muscle) which may counterbalance the decrease of fat mass. Another analysis missing was enucleating the obese group to see for a particular response of CRP levels. So, the reader continues to suspect that part of the effect of exercise training on CRP levels is related to the concomitant weight loss. Okita et al1 stated, and we agree, that there might be an optimal pace of exercise and weight loss to optimize the inflammatory status which needs to be examined in long-term intervention studies. In any case, two such studies escaped his attention. We have demonstrated in two intervention studies of 2-year follow-up in obese women4 and men5 that a multidisciplinary program of changes in lifestyle designed to obtain a substantial reduction in body weight through caloric restriction and increased …

Can exercise training with weight loss lower serum C-reactive protein levels?

C-reactive protein (CRP), an obesity-related inflammatory marker, is a promising predictor for cardiovascular disease and may be a mediator for atherogenesis. It has been reported that diet-induced weight loss lowered CRP levels. However, the effect of exercise training, another therapy that can reduce weight, on CRP is still unclear. We examined effects of exercise training with weight loss on CRP levels and conventional cardiovascular risks. A total of 227 apparently healthy women were recruited, and 199 subjects (average age 52 years) completed a 2-month weight reduction program consisting of supervised aerobic exercises. After the program, weight was reduced from 65.8 to 62.8 kg (P<0.0001), and all conventional variables were remarkably improved. Similarly, CRP levels were significantly decreased, from 0.63 (0.28 to 1.19) to 0.41 (0.18 to 0.80) mg/L (P<0.0001). However, in contrast to other variables, the changes in CRP levels were not proportionally associated with the extent of weight reduction. In the quartile analysis of % weight reduction, the largest weight reduction quartile did not show significant decreases in CRP levels, whereas moderate quartile showed remarkable CRP decreases. Exercise training with weight reduction disproportionately lowered CRP levels. Considering inflammatory status, there might be an optimal pace of exercise with weight loss.

Clinical evaluation of peak endocardial acceleration as a sensor for rate responsive pacing.

An innovative control parameter for rate responsive (RR) pacing that uses a sensor to measure mechanical vibrations generated by the myocardium during the isovolumetric contraction phase (peak endocardial acceleration [PEA]), has been devised by SORIN Biomedica (BEST Living System). To assess the physiological sensitivity of the pacemaker sensor along with reliability of the algorithm to supply appropriate pacing rates three different relationships were examined (linear regression analysis): (1) recorded deltaPEA exercise steps against the calculated energy cost of exercise (MET), (2) exercise pacing rates against predicted values, and (3) deltaPEA against exercise pacing rates. Fifteen patients (mean age 68 +/- 12 years) in NYHA Class I-II, implanted with the BEST Living System (Living 1 DDDR pacemaker) for advanced AVB and/or SSS, underwent one of the following maximal exercise stress protocols: bicycle (25 W, 2-minute steps) or Bruce or Chronotropic Assessment Exercise Protocol (CAEP). Pacing rates for each step were matched against those predicted by a reliable and tested custom software called Pacing Rate Profile Software (PRPS). The PRPS is based on the oxygen pulse reserve (OPR) method (OPR = VO2 reserve divided by heart rate reserve), American College of Sports Medicine (ACSM) formulas for calculating workload/metabolic requirements, and data derived from the Weber functional classes. On the basis of certain patient, data the PRPS then supplies appropriate metabolic pacing rate profiles. In all 15 patients linear regression analysis of deltaPEA against MET, as evaluated during the exercise protocol steps, showed a high correlation (r = 0.97). Likewise, a high correlation was also obtained between PRPS predicted heart rates and exercise pacing rates (r = 0.96) and PEA against exercise pacing rates (r = 0.96). The results of this study show that, through PEA dynamic monitoring, the SORIN Best Living System produces physiological pacing rates that are significantly related to metabolic needs.

Effect of lower limb exercise and cardiac pacing on forearm blood flow: Contribution of nitric oxide (NO)?

Effect of lower limb exercise and cardiac pacing on forearm blood flow: Contribution of nitric oxide (NO)?

T wave alternans for ventricular arrhythmia risk stratification.

Identifying patients at high risk of sudden cardiac death is an important goal, given the magnitude of this problem. In this regard, T wave alternans (TWA) is a heart-rate-dependent measure of arrhythmia vulnerability. The predictive accuracy of this test is maximal at heart rates between 100 and 120 bpm, which are usually achieved with exercise or atrial pacing. TWA has been shown to predict inducibility of ventricular tachycardia with programmed stimulation and to predict spontaneous arrhythmic events. This test has been applied to diverse populations, including patients with coronary artery disease, nonischemic cardiomyopathy, congestive heart failure, and status post implantable defibrillators. Despite these encouraging results, the role of TWA to guide clinical therapy still must be better elucidated.

Cardiac Output, Stroke Volume, and Pacing Rate: A Review of the Literature and a Proposed Technique for Selection of the Optimum Pacing Rate for an Exercise Responsive Pacemaker

Cardiac Output and Pacing Rate. Introduction: The purpose of this report is to determine the optimal pacing rate for an exercising patient. Methods and Results: From a review of the literature and from our own animal studies, the relationship between cardiac output and pacing rate and that between stroke volume and pacing rate are examined in resting and exercising animal and human subjects. With an adequately wide range of pacing rates, there exists a three‐phase relationship between cardiac output and pacing rate. Starting with a low pacing pacing rate, an increase in pacing results in an increase in cardaac output (phase 1), then little change in cardiac output (phase 2), after which there is a decrease in cardiac output (phase 3). However, the relationship between stroke volume and pacing rate does not typically exhibit characteristics that allow identification of the three phases. In resting subjects with impaired ventricles and in exercising subjects, phase 2 is narrow or absent, the cardiac output increasing, then decreasing with an increase in pacing rate. From the experimental data reviewed herein, a technique is proposed for identifying the starting point in selecting the best pacing rate for resting and exercising subjects. The technique relies on identification of the transitions in the three‐phase relationship between cardiac output and pacing rate. Conclusion: The best resting pacing rate is at the lower end of phase 2. A tentative first‐choice exercise rate is at the middle of the resting phase 2 region. However, a change in cardiac output with a change in pacing rate will allow refinement of this first‐choice exercise pacing rate.