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The effects of exercise modality during additional 'high-intensity interval training' upon aerobic fitness and strength in powerlifting and strongman athletes
Abstract
Powerlifters and strongman athletes have a necessity for optimal levels of muscular strength whilst maintaining sufficient aerobic capacity to perform and recover between events. HIIT has been popularized for its efficacy in improving both aerobic fitness and strength but never assessed within the aforementioned population group. The present study looked to compare the effect of exercise modality, e.g. a traditional aerobic mode (AM), and strength mode, (SM), during HIIT upon aerobic fitness and strength. Sixteen well resistance trained male participants, currently competing in powerlifting and strongman events, completed 8 weeks of approximately effort- and volume-matched HIIT in 2 groups: AM (cycling, n=8) and SM (resistance training, n=8). Aerobic fitness was measured as predicted V O_2Max using the YMCA 3 minute step test and strength as predicted 1RM from a 4-6RM test using a leg extension. Both groups showed significant improvements in both strength and aerobic fitness. There was a significant between-group difference for aerobic fitness improvements favoring the AM group (p<0.05). There was no between-group difference for change in strength. Magnitude of change using within group effect size (ES) for aerobic fitness and strength were considered large for each group (aerobic fitness, AM = 2.6, SM = 2.0; strength, AM = 1.9, SM = 1.8). In conclusion, our results support enhanced strength and aerobic fitness irrespective of exercise modality (e.g. traditional aerobic and resistance training). However, powerlifters and strongman athletes wishing to enhance their aerobic fitness should consider HIIT using an aerobic HIIT mode.
... However, to date, research examining this is limited. Only two studies have been published to our knowledge (Álvarez et al., 2017;Androulakis-Korakakis et al., 2018); though, our lab and others have been conducting research in this area, the initial findings of three further studies are also presented below. ...
... For changes in VO 2 peak, however, there was a statistically significant between-group difference (F (1,22) = 5.926, p = 0.023) revealing greater increase for the cycle ergometer group [estimated marginal mean (95% CIs) Δ = 5.66 ml.kg.min −1 (2.63 to 8.68)] compared with the leg press group [estimated marginal mean (95% CIs) Δ = 1.23 ml.kg.min −1 (−1.92 to 4.38)]. Considering the different training and testing modality, this change is interesting and contradicts results reported by others regarding changes in cardiorespiratory fitness measured with a range of tests and using effort matched protocols (Álvarez et al., 2017;Gil-Sotomayor et al., 2018), including those in trained populations (Androulakis-Korakakis et al., 2018). However, the study by Silva et al. (2019) there was considerable variation in maximal criteria from the incremental treadmill protocol with none of the participants reaching a respiratory exchange ratio >1.15 and also a number of participants showing differences in end of test max heart rate (>10 beats.min ...
... Considering the pattern of findings from this emerging body of research, there does seem to be evidence supporting the hypothesis of physiological adaptations and responses being primarily determined by effort, and less influenced by modality. In fact, random effects meta-analysis 3 comparing effect sizes between "cardio" and resistance training modalities for 4 of the studies discussed above (Álvarez et al., 2017;Androulakis-Korakakis et al., 2018;Silva et al., 2019;Armes et al., unpublished) seem to support that presently there is little evidence suggesting a difference between modalities when effort is controlled for. For strength, the effect size favored resistance training with a small effect (though this was not significant with the robust estimate) though with moderate precision for the estimate (Figure 2) and trivially for changes in cardiorespiratory fitness measures in "cardio" training (Figure 3). ...
Prolonged periods in microgravity (μG) environments result in deconditioning of numerous physiological systems, particularly muscle at molecular, single fiber, and whole muscle levels. This deconditioning leads to loss of strength and cardiorespiratory fitness. Loading muscle produces mechanical tension with resultant mechanotransduction initiating molecular signaling that stimulates adaptations in muscle. Exercise can reverse deconditioning resultant from phases of detraining, de-loading, or immobilization. On Earth, applications of loading using exercise models are common, as well as in μG settings as countermeasures to deconditioning. The primary modalities include, but are not limited to, aerobic training (or “cardio”) and resistance training, and have historically been dichotomized; the former primarily thought to improve cardiorespiratory fitness, and the latter primarily improving strength and muscle size. However, recent work questions this dichotomy, suggesting adaptations to loading through exercise are affected by intensity of effort independent of modality. Furthermore, similar adaptations may occur where sufficient intensity of effort is used. Traditional countermeasures for μG-induced deconditioning have focused upon engineering-based solutions to enable application of traditional models of exercise. Yet, contemporary developments in understanding of the applications, and subsequent adaptations, to exercise induced muscular loading in terrestrial settings have advanced such in recent years that it may be appropriate to revisit the evidence to inform how exercise can used in μG. With the planned decommissioning of the International Space Station as early as 2024 and future goals of manned moon and Mars missions, efficiency of resources must be prioritized. Engineering-based solutions to apply exercise modalities inevitably present issues relating to devices mass, size, energy use, heat production, and ultimately cost. It is necessary to identify exercise countermeasures to combat deconditioning while limiting these issues. As such, this brief narrative review considers recent developments in our understanding of skeletal muscle adaptation to loading through exercise from studies conducted in terrestrial settings, and their applications in μG environments. We consider the role of intensity of effort, comparisons of exercise modalities, the need for concurrent exercise approaches, and other issues often not considered in terrestrial exercise studies but are of concern in μG environments (i.e., O2 consumption, CO2 production, and energy costs of exercise).
... Indeed most comparisons have lacked parity in variables such as effort and duration. As noted, effort may be of importance and where this has been controlled between interventions (e.g., 'high intensity interval training' and high effort resistance training), recent work suggests that there may be little difference in the adaptations produced ( Androulakis-Korakkakis et al., 2017;Álvarez et al., 2017). Many of the physiological responses may be similar between exercise modes, assuming variables such as intensity of effort are controlled, and if this is the case, different modes may therefore result in similar adaptations. ...
... Resistance training is typically performed with a relatively high effort (though not always) and with varying durations, and 'cardio' exercise is typically performed with a low to moderate effort and high durations. Yet a recent study has suggested that, when performed in an effort and duration matched manner, eight weeks additional resistance training mode (squats and deadlifts), or 'cardio' exercise mode (upright cycle ergometry) 'high intensity interval training' produces largely similar improvements in cardiorespiratory fitness and knee extension strength in powerlifting and strongman athletes ( Androulakis-Korakkakis et al., 2017). Considering the highly trained nature of the population in that study, similar results might occur in an untrained population. ...
The present study examined the effects of exercise utilising traditional resistance training (leg press) or 'cardio' exercise (recumbent cycle ergometry) modalities upon acute physiological responses. Nine healthy males underwent a within session randomised crossover design where they completed both the leg press and recumbent cycle ergometer conditions. Conditions were approximately matched for effort and duration (leg press: 4 × 12RM using a 2 s concentric and 3 s eccentric repetition duration controlled with a metronome, thus each set lasted 60 s; recumbent cycle ergometer: 4 × 60 s bouts using a resistance level permitting 80-100 rpm but culminating with being unable to sustain the minimum cadence for the final 5-10 s). Measurements included VO 2 , respiratory exchange ratio (RER), blood lactate, energy expenditure, muscle swelling, and electromyography. Perceived effort was similar between conditions and thus both were well matched with respect to effort. There were no significant effects by 'condition' in any of the physiological responses examined (all p > 0.05). The present study shows that, when both effort and duration are matched, resistance training (leg press) and 'cardio' exercise (recumbent cycle ergometry) may produce largely similar responses in VO 2 , RER, blood lactate, energy expenditure, muscle swelling, and electromyography. It therefore seems reasonable to suggest that both may offer a similar stimulus to produce chronic physiological adaptations in outcomes such as cardiorespiratory fitness, strength, and hypertrophy. Future work should look to both replicate the study conducted here with respect to the same, and additional physiological measures, and rigorously test the comparative efficacy of effort and duration matched exercise of differing modalities with respect to chronic improvements in physiological fitness
... Sports have been evolving and innovating since time immemorial, whether in the form of improved sports equipment, various training methods or the use of modern technologies. In terms of training methods, we can observe the increasing popularity of high intensity interval training (HIIT) programs, which combine load intervals performed at a high intensity with intervals of rest [1][2][3][4][5]. They can also be performed using many types of equipment and exercises, such as bicycles, treadmills, running, free weights and sailor's ropes, as well as exercises that use one's own body weight as a means of resistance [6][7][8]. ...
Objectives: This paper aimed to assess the motor performance in the Burpee Movement Program through the acceleration recorded by the Phyphox mobile app and define its relationship to strength and endurance parameters. Methods: Altogether, 15 students in physical education teaching completed the 3 × 3 min Burpee Movement Program, consisting of the repeated execution of a single burpee with maximum effort at regular intervals triggered by a sound signal. During the load phase, the intensity of the burpee and the fatigue index expressed in percentages were evaluated by means of the acceleration recorded through a mobile phone. In the second part of testing, we evaluated the performance parameters during a bench press and squat where the intensity was measured using a linear displacement transducer (Tendo Power Analyzer) and aerobic endurance was assessed with a 20 m shuttle run test (20 mSR). Results: The average intensity of the burpee ranged from 3.12 to 11.12 ms−2. The fatigue index ranged from −21.95% (which represented an increase in performance) to 33.63% (which represented a decrease in performance). The performances in the bench presses ranged from 58 to 480 W and from 175 to 696 W during the squats. The distance in the 20 m shuttle run test (20 mSR) ranged from 540 to 2000 m. The intensity of the burpee showed a significant correlation to the performances achieved in the bench presses and squats r = 0.82 and 0.79. The fatigue index showed a significant correlation to the 20 m shuttle run test (20 mSR) r = −0.67. Conclusions: These findings indicate that in, our case, the results from the Burpee Movement Program are significantly associated with the participants’ strength and endurance abilities. We recommend using BMP for the development of strength–endurance abilities, but further exploration is needed regarding the potential use of BMP as a diagnostic test.
... Good posture dynamics is clinically associated with pain [1] , proper breathing [2] , digestion [3] , circulatory system [4]. More Athletes and gym goers are taking up the powerlifting exercises to increase the muscle strength and fitness [5]. Powerlifters usually prone with acute and chronic injuries. ...
With unprecedented witness in physical exercises, gyms are high in demand with their infrastructure and best exercise equipment to provide proper fitness to its customers. But incorrect posture is one of the overlooked issues that result in acute or chronic injuries while doing improper exercises. Heavy loads and wrong postures during the exercise are not monitored mostly due to insufficient assessment tools or infrastructure. The gait analysis setup makes it impossible to monitor exercise routines in regular gyms due to the space and expenditure. In this study, a wearable device integrated with multiple accelerometers is designed to monitor posture. This portable device can also deliver proper data for routines like squats, bench press, and deadlifts. Using built-in Bluetooth and Wi-Fi, the data can be tracked in real time. The real-time posture data can provide reliable information to the gym coaches for immediate correction remedy.
... While acknowledging the limitations of our study's 475 cross-sectional design, our findings do not fully support the concept of an interference effect with concurrent training, as HIFT participants were observed to have the favorable health and performance-related benefits of focusing on either strength or endurance training alone. Our findings are in accordance 480 with other studies that suggest performing HIIT-based concurrent training does not impact hypertrophy and strength development (Androulakis-Korakakis et al., 2018;Gentil et al., 2017). ...
Purpose: We compared aerobic capacity (V˙O2max), mitochondrial capacity (mV˙O2), anaerobic power, strength, and muscle endurance in healthy, active men from strength (STR), endurance (END) and high-intensity functional training (HIFT) backgrounds. Methods: Twenty-four men (n = 8/group) completed a cycle ergometer test to determine V˙O2max, followed by a 3-min all-out test to determine peak (PP) and end power (EP), and to estimate anaerobic [work done above EP (WEP)] and aerobic work capacity. Strength was determined by knee extensor maximal voluntary contraction at various flexion angles. The endurance index (EI) of the vastus lateralis (VL) was assessed by measuring muscle contraction acceleration during electrical twitch mechanomyography. mV˙O2max of the VL was assessed using near-infrared spectroscopy to estimate muscle oxygen consumption during transient femoral artery occlusions. Results: V˙O2max was significantly different among groups (p < .05). PP was significantly higher in HIFT and STR versus END (p < .05). EP was significantly higher in HIFT and END compared to STR (p < .05). WEP was significantly higher in STR compared to END (p < .05), whereas total work done was significantly higher in HIFT and END compared to STR (p < .05). mV˙O2max and EI were comparable between HIFT and END but significantly lower in STR versus END (p < .05). Torque production was significantly lower in END compared to STR and HIFT at all flexion angles (p < .05), with no difference between STR and HIFT. Conclusion: HIFT participants can exert similar power outputs and absolute strength compared to strength focused participants but exhibit fatigue resistance and mitochondrial capacity comparable to those who train for endurance.
... Concurrent exercise interventions (e.g. team sport and running) will be excluded as these interventions alongside RT may interfere with muscle strength adaptations [53]. Studies that include the prescription of abdominal exercises will be included, however, the actual abdominal exercises will be excluded from the calculation of dose, dosing, and dosage as the intensity of these exercises cannot be accurately quantified. ...
Examinations of the effect of resistance training (RT) on muscle strength have attempted to determine differences between prescriptions, mostly examining individual training variables. The broad interaction of variables does not appear to be completely considered, nor has a dose-response function been determined. This registered (doi.org/10.17605/OSF.IO/EH94V) systematic review with meta-analysis aims to determine if the interaction of individual training variables to derive RT dose, dosing, and dosage can influence muscle strength and determine if an optimal prescription range exists for developing muscle strength. To derive RT dose, the following calculation will be implemented: number of sets × number of repetitions × number of exercises × exercise intensity, while RT dosing factors in frequency and RT dosage considers program duration. A keyword search strategy utilising interchangeable terms for population (adult), intervention (resistance training), and outcomes (strength) will be conducted across three databases (CINAHL, MEDLINE, and SPORTDiscus). Novel to the field of exercise prescription, an analytical approach to determine the dose-response function for continuous outcomes will be used. The pooled standardised mean differences for muscle strength will be estimated using DerSimonian and Laird random effects method. Linear and non-linear dose-response relationships will be estimated by fitting fixed effects and random effects models using the one-stage approach to evaluate if there is a relationship between exercise dose, dosing and dosage and the effect on muscle strength. Maximised log-likelihood and the Akaike Information Criteria will be used to compare alternative best fitting models. Meta regressions will investigate between-study variances and a funnel plot and Egger’s test will assess publication bias. The results from this study will identify if an optimal prescription range for dose, dosing and dosage exists to develop muscle strength.
... Where studies have matched effort and duration, but used testing outcomes favouring the RT intervention there seems to be greater strength changes for RT compared to AT (Álvarez et al., 2017;Gil-Sotomayor et al., 2018). Similarly to the findings reported here, where effort and duration have been matched but the testing outcome was independent of either intervention, strength changes appear to be largely similar (Androulakis-Korakakis et al., 2017). The comparative strength adaptations may result from similar neuromuscular stimulus in both modalities when effort and duration are matched. ...
The aim of this study was to compare two different maximal intensity exercise modality training protocols of similar durations on muscle strength, cardiorespiratory fitness, and lower limb composition in recreationally trained men. Twenty-five trained men (28.9 ± 5.6 years) were randomly divided into Cycle ergometer (4 sets of 30 seconds sprints) and Leg press (4 sets of 10–12 repetitions to momentary failure). Both groups trained three times a week for 5 weeks. Before and after the training period, the participants performed a 10-repetition maximum (10RM) test for knee extension, an incremental exercise test on a treadmill for time to exhaustion (TTE) and peak oxygen consumption (V˙O2peak) and underwent dual energy X-ray absorptiometry to assess lower limb composition. Knee extension 10RM and TTE increased in both groups with no statistically significant between group (p = 0.614 and p = 0.210). Only cycle ergometer group increased V˙O2peak (p = 0,012). For all lower limb composition outcomes, changes were minimal. The results suggest that 5 weeks of effort and duration matched exercise protocols using cycle ergometer training or leg press may produce similar strength adaptations.
... The used type of physical effort is significant for people with full motor skills and is the key in the motor training process of people with physical disabilities. Many forms of physical activity have a mixed type of effort (swimming, basketball, volleyball, dance) [16]; however, there are those where static and strength effort prevails, for example during lifting weights [16][17][18][19]. The effort applied during physical activity affects the quality of endurance, cardio-respiratory capacity and strength [20]. ...
Background: The issue of scientific measurement of somatotypes of athletes with physical disabilities and the type of physical activity undertaken by them is poorly documented in the literature. The aim of the study is to determine what type of body composition is characteristic of athletes with physical disabilities, engaging in various types of physical activity, such as swimming, sitting volleyball and weight lifting.
Material and methods: Sixty men, aged 20-30, were qualified for the study. Each study participant had a motor dysfunction and was in intellectual norm. For the research protocol, Sheldon’s typology in Heath and Carter modification was used.
Results: The group of men with physical disabilities practicing swimming regularly had the advantage of endomorphic and mesomorphic components. A similar distribution of components in the somatotype was demonstrated by men playing sitting volleyball. Men lifting weights clearly showed the dominance of the mesomorphic component and, to a small extent, the share of the ectomorphic and endomorphic components.
Conclusions: A properly calculated somatotype allows disabled athletes to learn about body composition components and to train and develop more effectively in a particular physical activity.
... In the current study, HIIT, with or without high-protein diet, improved maximal exercise capacity and muscle power in middle-aged individuals with obesity. The finding of the improvement of maximal exercise capacity in middle-aged individuals with obesity with HIIT is consistent with other studies where HIIT was shown to improve cardiorespiratory fitness in young athletes, adults with obesity, and patients with coronary artery diseases and heart failure (23,34,35). The improvement of muscle power after HIIT is likely due to the high-intensity component of the program was achieved by increasing the load and velocity of the spinning, thus challenging the neuromuscular system that produces high muscle power. ...
Background
Obesity accelerates and exacerbates the age-related changes on muscle function and exercise capacity. In addition, the middle-aged population is often overlooked when talking about the prevention of sarcopenia. This study investigated the effects of exercise alone or in combination with a high-protein diet on muscle function and physical fitness in middle-aged obese adults.Materials and methodsSixty-nine middle-aged (501–64 years old) obese adults were randomly assigned to one of the following groups: control group (C; n=23), exercise group (E; n=23) or exercise plus high-protein group (EP; n=23). Individuals within the E and EP groups received 12 weeks of exercise training; whereas, the individuals in the EP group also received a highprotein diet intervention (1.6g/kg/day). Individuals within the C group were asked to maintain their lifestyle for 12 weeks. Participants were evaluated before and after the intervention. Outcome measures included maximal exercise capacity, muscle function and functional physical performance. Analysis of covariance was used to determine the effects of the intervention.ResultsAfter the intervention, the E and EP groups had greater maximal work rate, peak oxygen consumption, and muscle power during muscle contractions at 180°/sec than that in the C group (P<0.05). The EP group, but not the E group, showed significant improvement in the sit-to-stand test and climbing stairs test than the C group after the intervention (P<0.05). Within group comparisons showed that the anaerobic threshold only increased in the EP group (+12% from pre-test).Conclusions
For middle-aged obese adults, exercise with a high-protein diet not only improved muscle power and exercise capacity but also enhanced their functional physical performance.
... Leg cycling exercise interventions in individuals with motor dysfunction have shown that the effects of leg cycling exercise training can be translated into improved postural control in standing and better function during daily activities involving the lower extremities, such as walking speed and endurance (Katz-Leurer et al., 2006;Yang et al., 2014). It is also commonly used in athlete training for improving physical fitness (Jones et al., 2015;Paquette et al., 2017;Androulakis-Korakakis et al., 2018). ...
Leg cycling is one of the most common modes of exercise used in athletics and rehabilitation. This study used a novel cycling setting to elucidate the mechanisms, central vs. peripheral fatigue induced by different resistance with equivalent works (watt∗min). Twelve male adults received low and relatively high resistance cycling fatigue tests until exhausted (RPE > 18) in 2 weeks. The maximal voluntary contraction, voluntary activation level, and twitch forces were measured immediately before and after cycling to calculate General (GFI), central (CFI), and peripheral (PFI) fatigue indices of knee extensors, respectively. The results showed that the CFI (high: 92.26 ± 8.67%, low: 78.32 ± 11.77%, p = 0.004) and PFI (high: 73.76 ± 17.32%, low: 89.63 ± 11.01%, p < 0.017) were specific to the resistance of fatigue protocol. The GFI is influenced by the resistance of cycling to support the equivalent dosage. This study concluded that the mechanism of fatigue would be influenced by the resistance of fatigue protocol although the total works had been controlled.
... Due to the multi-modal approach to this training methodology, it is important to note the increases in maximal oxygen consumption. Androulakis-Korakakis et al. 38 found that increases in maximal aerobic capacity are possible when adding in variations of high-intensity interval training in experienced powerlifting and strongman competitors. Bellar et al. 39 found that a task priority training session and performance success was associated with CF experience, but time priority-sessions and performance is associated with maximal oxygen consumption. ...
Purpose: The purpose of this investigation is to determine the effectiveness of heart-rate variability as a monitoring and intensity-prescription tool for CrossFit.
Methods: Twenty-five recreational trained males and females were randomized into two groups, experimental (EXP) and control (CON) prior to the intervention. Prior to any assessments, all participants established a 14-day baseline period for their morning heart-rate variability. Both groups underwent pre-training assessment for work capacity, whole body strength, maximal oxygen consumption and body composition. All participants followed a 21-day training program followed by another week of testing, repeated twice. During the training, a rolling seven-day average of heart-rate variability was used to prescribed based upon windows set at .5 and 1 SD of the baseline average with the windows adjusting after the first training block. EXP would have full-intensity, moderated-intensity, or active recovery training sessions based upon morning heart-rate variability while CON always trained at full intensity/effort.
Results: There were no significant group by time interactions for any variables, but there was a significantly different amount of training sessions at a full intensity. All participants saw increases performance outcomes, while seeing significant improvement in physical work capacity, and EXP seeing positive outcomes in body composition measures.
Conclusion: Heart-rate variability is an effective tool for monitoring participants and prescribing-intensity in CrossFit Training.
... We can estimate the VO 2 max introducing the final heart rate after the effort applying a specific equation by sex and age [88]. It has been used in some recent studies [89,90]. ...
Aging is a natural, physiological, and inevitable process, but it can be also influenced. Although aging is not a
disease, it has several characteristics that could indicate so, such as a functional decline at different levels, whichmay determine clinical manifestations, and it is associated with several disease processes. Consequently, it isessential to create and adopt strategies to delay the aging process. Nowadays, any strategy adopted without
including physical exercise seems inconceivable. Recent studies published in relation to this population have shown that the maintenance of acceptable levels of physical fitness is associated with the prevention of many of premature aging consequences, good rates of health, and quality of life of the person. cardiorespiratory fitness and muscular strength (as physical fitness components) are excellent life expectancy and quality of life predictors. Therefore, reaching a good fitness level is the most powerful clinical method to prevent and delay the aging process. Not only their years to live increase, but also their quality, with health and without diseases or mobility dependence.
Purpose
To determine how airway resistance (RAW) and airway conductance (GAW) affect inspiratory time (iT) and expiratory time (eT) in subjects with different nutritional states using the step test.
Methods
Forty-eight participants were recruited and divided into three groups: 16 normal weight (NW), 16 overweight (OW), and 16 obese (OB). A lung function test and anthropometric evaluation were performed. iT and eT were measured using a sonographic device before and after the step test.
Results
Body Mass Index (BMI) and Body Fat Percentage (BF%) were significantly higher (P<0.0001; P<0.0001, respectively) in OB group. RAW was significantly higher in the OB group (P=0.004), and GAW (P=0.004) was significantly lower in the same group. At rest, the Respiratory Rate (RR) was significantly higher in OB group (P<0.05), while iT and eT showed no significant differences. On the other hand, after the step test, eT was significantly lower (P=0.016), with the multiple linear regression model being the best predictor of post-exercise eT, including BF%/GAW and BF%/sGAW (explained variability of 15.7% and 14.6%, respectively).
Conclusion
Nutritional status can significantly impact lung function; at rest, there was a decrease in lung volumes and an increase in RR in OB subjects. In addition, there was a significant decrease in eT of OB subjects post-exercise. Finally, a significant relationship of BF%/GAW and BF%/sGAW with post-exercise eT was noted.
Background: Kidney disease (CKD) is a disorder in which the kidneys have been damaged and are unable tofilter blood as effectively as they should. As a result, extra fluid and waste from the circulation linger in the body,potentially leading to various health issues like heart disease and stroke. This also causes swelling in the lowerlimb causing reduced mobility and altered lung volume. This reduction in mobility can be improved with exercise.Aerobic training has been proved to be one of the most effective treatments for improving lung volume capacity.Aerobic training using cycling exercise can improve both lung volume capacity and mobility together.Purpose: To analyze the Effect of Aerobic training and lung volume and gait speed capacity in individuals withchronic kidney disease.Materials and Methods: Sixty individuals with chronic kidney disease were selected according to inclusionand exclusion criteria in which 48 individuals completed the study and 12 quit. These individuals were treatedwith bed side cycling and spirometry for 8 weeks, 1 session per day. Their Pretreatment Gait speed test scoring,3-minute walk test, were recorded. After the treatment duration the same test was repeated.Results: There is an Improvement in Gait speed and 3-minute walk test after giving incentive spirometry stage ofCKD Individuals. No adverse events were observed during and after the treatment.Conclusion: Individuals with CKD need aerobic training to improve their lung volume capacity. The currentstudy concludes that there is an improvement in Gait speed and 3-minute walk test after the treatment session ofincentive spirometry and Bedside cycle ergometer.Clinical Significance: This study’s clinical significance lies in assessing how aerobic training impacts lung volumecapacity in chronic kidney disease patients. Improved lung function may lead to better cardiovascular health,enhanced quality of life, and reduced complications. These findings could support tailored exercise programs toimprove the well-being and overall health of individuals with chronic kidney disease.
Systematic overload, which is a training characteristic of powerlifters with visual impairments of high qualification has a negative impact on the functioning of body systems and the course of the underlying and comorbidities. This determines the relevance of the scientific substantiation of training programs for athletes with visual impairments as the most important component of ensuring the achievement of sports results in powerlifting. This study aimed to experimentally substantiate the effectiveness of the impact of various training programs on physical fitness and athletic performance of powerlifters with visual impairments of high qualification. To solve the goal we used methods of analysis of scientific and methodological literature, pedagogical observation, pedagogical experiment and methods of mathematical statistics. The study involved 16 visually impaired athletes who were members of the national powerlifting team. The pedagogical experiment was based on testing the effectiveness of two training programs, which differed in the parameters of the load components in the annual training and macrocycle periods. After the pedagogical experiment, the experimental group showed reliable indicators of growth on all tests and improvement of sports results, and athletes of the control group increased physical fitness in three tests out of five and sports results are available only in squat and bench press. In both groups, the highest growth rates in the level of development of physical qualities were found in tests aimed at determining the level of development of strength and flexibility. Comparing the results of the introduction of various training programs in the training process of powerlifters with visual impairments, we can conclude that the performance of the experimental group is much higher than among the powerlifters of the control group.
Sistematsko preopterećenje, koje je karakteristika treninga powerliftera sa oštećenjima vida visoke kvalifikacije, negativno utiče na funkcionisanje tijela i tok osnovnog stanja vida i na pojavu komorbiditeta. Time se utvrđuje relevantnost naučnog utemeljenja programa treninga za sportiste sa oštećenjem vida kao najvažnije komponente osiguravanja postizanja sportskih rezultata u powerliftingu.
Ovo istraživanje imalo je za cilj eksperimentalno potkrijepiti učinkovitost uticaja različitih programa treninga na tjelesnu spremnost i atletske performanse powerliftera sa oštećenjem vida visoke kvalifikacije. Da bi se cilj ostvario, korištene su metode analize naučne i metodičke literature, pedagoško posmatranje, pedagoški eksperiment i metode matematičke statistike. U istraživanju je učestvovalo 16 slabovidnih sportista koji su bili članovi nacionalnog powerlifting tima. Eksperiment se temeljio na testiranju učinkovitosti dva programa treninga koji su se razlikovali u parametrima komponenti opterećenja u godišnjem trenažnom i makrociklusnom razdoblju. Eksperimentalna grupa je nakon eksperimenta pokazala pouzdane pokazatelje povećanja na svim testovima i poboljšanja sportskih rezultata, a sportisti kontrolne grupe povećali su fizičku spremnost u tri od pet testova (sportski rezultati dostupni su samo u čučnju i bench pressu). U obje grupe najveće stope rasta nivoa razvijenosti tjelesnih osobina utvrđene su u testovima za utvrđivanje stepena razvoja snage i fleksibilnosti. Upoređujući rezultate uvođenja različitih programa treninga u trenažni proces powerliftera sa oštećenjem vida, može se zaključiti da je učinak eksperimentalne grupe znatno veći nego kod powerliftera kontrolne grupe.
In resistance training, the ability to predict momentary task failure (MF; i.e. maximum effort) during submaximal exercise may be affected by congruence of how (sub-)maximal effort is perceived compared with the actual effort required. The present study examined participants with at least one year of resistance training experience predicting their proximity to MF in two different experiments using a deception design. Participants performed four trials of knee extensions with single sets to their self-determined repetition maximum (sdRM) and MF using a baseline 70%1RM in the first experiment (n = 14). Aiming to minimize participants’ variability in repetition performances, they performed at 70% of their daily MVC instead of their baseline 1RM in the second experiment (n = 24). Results suggested that participants typically under predicted the number of repetitions they could perform to MF. These results suggest that participants with at least one year of resistance training experience are not adequately accurate at gauging effort in submaximal conditions during the gestalt experience of resistance training. This suggests that perceptions of effort during RT task performance may not be congruent with the actual effort required. This has implications for controlling, programming and manipulating effort in RT and potentially on the magnitude of desired adaptations such as improvements in muscular hypertrophy and strength.
Prolonged periods in microgravity (μG) environments result in deconditioning of numerous physiological systems, particularly muscle at molecular, single fiber, and whole muscle levels. This deconditioning leads to loss of strength and cardiorespiratory fitness. Loading muscle produces mechanical tension with resultant mechanotransduction initiating molecular signaling that stimulates adaptations in muscle. Exercise can reverse deconditioning resultant from phases of de-training, de-loading, or immobilization. On earth, applications of loading using exercise models are common, as well as in μG settings as countermeasures to deconditioning. The two primary modalities, aerobic training (or ‘cardio’), and resistance training, have historically been dichotomized; the former primarily thought to improve cardiorespiratory fitness, and the latter primarily improving strength and muscle size. However, recent work questions this dichotomy, suggesting adaptations to loading through exercise are affected by intensity of effort independent of modality. Furthermore, similar adaptations may occur where sufficient intensity of effort is used. Traditional countermeasures for μG induced deconditioning have focused upon engineering based solutions to enable application of traditional models of exercise. Yet, contemporary developments in understanding of the applications, and subsequent adaptations, to exercise induced muscular loading in terrestrial settings have advanced such in recent years that it may be appropriate to revisit the evidence to inform how exercise can used in μG. With the planned decommissioning of the International Space Station as early as 2024 and future goals of manned moon and Mars missions, efficiency of resources must be prioritized. Engineering based solutions to apply exercise modalities inevitably present issues relating to devices mass, size, energy use, heat production, and ultimately cost. It is necessary to identify exercise countermeasures to combat deconditioning whilst limiting these issues. As such, this brief narrative review considers recent developments in our understanding of skeletal muscle adaptation to loading through exercise from studies conducted in terrestrial settings, and their applications in μG environments. We consider the role of intensity of effort, comparisons of exercise modalities and the need for concurrent exercise approaches, and other issues often not considered in terrestrial exercise studies but are of concern in μG environments (i.e. O2 consumption, CO2 production, and energy costs of exercise).
Objective: A growing area of discourse within sports medicine and resistance training is that of periodization. This has been represented as variation in load and subsequently repetitions as well as volume, with a view to maximize strength and hypertrophy adaptations. A number of recent review articles have attempted to draw overarching conclusions from the present body of literature in an effort to provide definitive guidelines. However, there are numerous variables within resistance training that are often overlooked, and in the context of periodization, might significantly impact adaptation. Design & Methods: Narrative Review Results: The present piece confers need for clarity in terminology of effort rather than intensity, as well as discussing how variety of load might impact volume-load, discomfort, muscle damage and recovery. Furthermore, this article discusses often overlooked variables such as variety in exercise selection, detraining periods, and supervision, which are all evidenced to impact strength and hypertrophy adaptations. Conclusions: Our opinion is that without inclusion of these variables any guidelines surrounding periodization for strength or hypertrophy are limited in application. We conclude by highlighting areas for future research, as well as practical recommendations within this field.
Our current state of knowledge regarding the load (lighter or heavier) lifted in resistance training programmes that will result in ‘optimal’ strength and hypertrophic adaptations is unclear. Despite this, position stands and recommendations are made based on, we propose, limited evidence to lift heavier weights. Here we discuss the state of evidence on the impact of load and how it, as a single variable, stimulates adaptations to take place and whether evidence for recommending heavier loads is available, well-defined, currently correctly interpreted or has been overlooked. Areas of discussion include electromyography amplitude, in vivo and in vitro methods of measuring hypertrophy, and motor schema and skill acquisition. The present piece clarifies to trainers and trainees the impact of these variables by discussing interpretation of synchronous and sequential motor unit recruitment and revisiting the size principle, poor agreement between whole-muscle cross-sectional area (CSA) and biopsy-determined changes in myofibril CSA, and neural adaptations around task specificity. Our opinion is that the practical implications of being able to self-select external load include reducing the need for specific facility memberships, motivating older persons or those who might be less confident using heavy loads, and allowing people to undertake home- or field-based resistance training intervention strategies that might ultimately improve exercise adherence.
Muscle strength is often measured through the performance of a one-repetition maximum (1RM). However, we that feel a true measurement of ‘strength’ remains elusive. For example, low-load alternatives to traditional resistance training result in muscle hypertrophic changes similar to those resulting from traditional high-load resistance training, with less robust changes observed with maximal strength measured by the 1RM. However, when strength is measured using a test to which both groups are ‘naive’, differences in strength become less apparent. We suggest that the 1RM is a specific skill, which will improve most when training incorporates its practice or when a lift is completed at a near-maximal load. Thus, if we only recognize increases in the 1RM as indicative of strength, we will overlook many effective and diverse alternatives to traditional high-load resistance training. We wish to suggest that multiple measurements of strength assessment be utilized in order to capture a more complete picture of the adaptation to resistance training.
High-intensity interval training (HIIT) is a time-efficient method of improving aerobic and anaerobic power and capacity. In most individuals, however, HIIT using modalities such as cycling, running, and rowing does not typically result in increased muscle strength, power, or endurance. The purpose of this study is to compare the physiological outcomes of traditional HIIT using rowing (Row-HIIT) with a novel multimodal HIIT (MM-HIIT) circuit incorporating multiple modalities, including strength exercises, within an interval. Twenty-eight recreationally active women (age 24.7 ± 5.4 years) completed 6 weeks of either Row-HIIT or MM-HIIT and were tested on multiple fitness parameters. MM-HIIT and Row-HIIT resulted in similar improvements (p < 0.05 for post hoc pre- vs. post-training increases for each group) in maximal aerobic power (7% vs. 5%), anaerobic threshold (13% vs. 12%), respiratory compensation threshold (7% vs. 5%), anaerobic power (15% vs. 12%), and anaerobic capacity (18% vs. 14%). The MM-HIIT group had significant (p < 0.01 for all) increases in squat (39%), press (27%), and deadlift (18%) strength, broad jump distance (6%), and squat endurance (280%), whereas the Row-HIIT group had no increase in any muscle performance variable (p values 0.33–0.90). Post-training, 1-repetition maximum (1RM) squat (64.2 ± 13.6 vs. 45.8 ± 16.2 kg, p = 0.02), 1RM press (33.2 ± 3.8 vs. 26.0 ± 9.6 kg, p = 0.01), and squat endurance (23.9 ± 12.3 vs. 10.2 ± 5.6 reps, p < 0.01) were greater in the MM-HIIT group than in the Row-HIIT group. MM-HIIT resulted in similar aerobic and anaerobic adaptations but greater muscle performance increases than Row-HIIT in recreationally active women.
Background:
The efficacy of high-intensity interval training for a broad spectrum of cardio-metabolic health outcomes is not in question. Rather, the effectiveness of this form of exercise is at stake. In this paper we debate the issues concerning the likely success or failure of high-intensity interval training interventions for population-level health promotion.
Discussion:
Biddle maintains that high-intensity interval training cannot be a viable public health strategy as it will not be adopted or maintained by many people. This conclusion is based on an analysis of perceptions of competence, the psychologically aversive nature of high-intensity exercise, the affective component of attitudes, the less conscious elements of motivated behaviour that reflect our likes and dislikes, and analysis using the RE-AIM framework. Batterham argues that this appraisal is based on a constrained and outmoded definition of high-intensity interval training and that truly practical and scalable protocols have been - and continue to be - developed. He contends that the purported displeasure associated with this type of exercise has been overstated. Biddle suggests that the way forward is to help the least active become more active rather than the already active to do more. Batterham claims that traditional physical activity promotion has been a spectacular failure. He proposes that, within an evolutionary health promotion framework, high-intensity interval training could be a successful population strategy for producing rapid physiological adaptations benefiting public health, independent of changes in total physical activity energy expenditure.
Summary:
Biddle recommends that we focus our attention elsewhere if we want population-level gains in physical activity impacting public health. His conclusion is based on his belief that high-intensity interval training interventions will have limited reach, effectiveness, and adoption, and poor implementation and maintenance. In contrast, Batterham maintains that there is genuine potential for scalable, enjoyable high-intensity interval exercise interventions to contribute substantially to addressing areas of public health priority, including prevention and treatment of Type 2 diabetes and cardiovascular disease.
Introduction: CrossFit® training sessions are often performed using either high-intensity continuous (circuit) or interval training (HIIT) methods and have been shown to elicit large increases in cardiovascular fitness. The acute responses of these different types of workouts, however, have not been reported. The purpose of this preliminary study was to a) describe and compare the heart rate (HR) and perceived exertion (RPE) responses to two different CrossFit-based multimodal exercise sessions: circuit (MMCIR) and high-intensity interval (MMHIIT) sessions; and b) examine the differences in responses by novice compared to experienced participants.
Background Enhancing cardiovascular fitness can lead to substantial health benefits. High-intensity interval training (HIT) is an efficient way to develop cardiovascular fitness, yet comparisons between this type of training with traditional endurance training are equivocal.
Objective Our objective was to meta-analyse the effects of endurance training and HIT on the maximal oxygen consumption (VO2max) of healthy, young to middle-aged adults.
Methods Six electronic databases were searched (MEDLINE, PubMed, SPORTDiscus, Web of Science, CINAHL and Google Scholar) for original research articles. A search was conducted and search terms included ‘high intensity’, ‘HIT’, ‘sprint interval training’, ‘endurance training’, ‘peak oxygen uptake’, ‘VO2max’. Inclusion criteria were controlled trials, healthy adults aged 18-45 y, training duration ≥2 weeks, VO2max assessed pre- and post-training. Twenty-eight studies met the inclusion criteria and were included in the meta-analysis. This resulted in 723 participants with a mean ± SD age and initial fitness of 25.1 ± 5 y and 40.8 ± 7.9 mL•kg-1•min-1, respectively. We made probabilistic magnitude-based inferences for meta-analysed effects based on standardized thresholds for small, moderate and large changes (0.2, 0.6 and 1.2, respectively) derived from between-subject standard deviations (SDs) for baseline VO2max.
Results The meta-analysed effect of endurance training on VO2max was a possibly large beneficial effect (4.9 mL•kg-1•min-1; 95% confidence limits ±1.4 mL•kg-1•min-1), when compared with no exercise controls. A possibly moderate additional increase was observed for typically younger subjects (2.4 mL•kg-1•min-1; ±2.1 mL•kg-1•min-1) and interventions of longer duration (2.2 mL•kg-1•min-1; ±3.0 mL•kg-1•min-1), and a small additional improvement for subjects with lower baseline fitness (1.4 mL•kg-1•min-1; ±2.0 mL•kg-1•min-1). When compared to no exercise controls, there was likely large beneficial effect of HIT (5.5 mL•kg-1•min-1; ±1.2 mL•kg-1•min-1), with a likely moderate greater additional increase for subjects with lower baseline fitness (3.2 mL•kg-1•min-1; ±1.9 mL•kg-1•min-1) and interventions of longer duration (3.0 mL•kg-1•min-1; ±1.9 mL•kg-1•min-1), and a small lesser effect for typically longer HIT repetitions (-1.8 mL•kg-1•min-1; ±2.7 mL•kg-1•min-1). The modifying effects of age (0.8 mL•kg-1•min-1; ±2.1 mL•kg-1•min-1) and work:rest ratio (0.5 mL•kg-1•min-1; ±1.6 mL•kg-1•min-1) were unclear. When compared to endurance training, there was a possibly small beneficial effect for HIT (1.2 mL•kg-1•min-1; ±0.9 mL•kg-1•min-1) with small additional improvements for typically longer HIT repetitions (2.2 mL•kg-1•min-1; ±2.1 mL•kg-1•min-1), older subjects (1.8 mL•kg-1•min-1; ±1.7 mL•kg-1•min-1), interventions of longer duration (1.7 mL•kg-1•min-1; ±1.7 mL•kg-1•min-1), greater work:rest ratio (1.6 mL•kg-1•min-1; ±1.5 mL•kg-1•min-1) and lower baseline fitness (0.8 mL•kg-1•min-1; ±1.3 mL•kg-1•min-1).
Conclusion Endurance training and HIT both elicit large improvements in the VO2max of healthy, young to middle-aged adults with the gains in VO2max being greater following HIT, when compared to endurance training.
While the physiological adaptations that occur following endurance training in previously sedentary and recreationally active individuals are relatively well understood, the adaptations to training in already highly trained endurance athletes remain unclear. While significant improvements in endurance performance and corresponding physiological markers are evident following submaximal endurance training in sedentary and recreationally active groups, an additional increase in submaximal training (i.e. volume) in highly trained individuals does not appear to further enhance either endurance performance or associated physiological variables [e.g. peak oxygen uptake (V̇O2peak), oxidative enzyme activity]. It seems that, for athletes who are already trained, improvements in endurance performance can be achieved only through high-intensity interval training (HIT). The limited research which has examined changes in muscle enzyme activity in highly trained athletes, following HIT, has revealed no change in oxidative or glycolytic enzyme activity, despite significant improvements in endurance performance (p 2max is achieved (Vmax) as the interval intensity, and fractions (50 to 75%) of the time to exhaustion at Vmax (Tmax) as the interval duration has been successful in eliciting improvements in performance in long-distance runners. However, Vmax and Tmax have not been used with cyclists. Instead, HIT programme optimisation research in cyclists has revealed that repeated supramaximal sprinting may be equally effective as more traditional HIT programmes for eliciting improvements in endurance performance. Further examination of the biochemical and physiological adaptations which accompany different HIT programmes, as well as investigation into the optimal HIT programme for eliciting performance enhancements in highly trained athletes is required.
The purpose of this study was to compare the effect of low- versus high-load resistance training (RT) on muscular adaptations in well-trained subjects. Eighteen young men experienced in RT were matched according to baseline strength, and then randomly assigned to 1 of 2 experimental groups: a low-load RT routine (LL) where 25-35 repetitions were performed per set per exercise (n = 9), or a high-load RT routine (HL) where 8-12 repetitions were performed per set per exercise (n = 9). During each session, subjects in both groups performed 3 sets of 7 different exercises representing all major muscles. Training was carried out 3 times per week on non-consecutive days, for 8 total weeks. Both HL and LL conditions produced significant increases in thickness of the elbow flexors (5.3 vs. 8.6%, respectively), elbow extensors (6.0 vs. 5.2%, respectively), and quadriceps femoris (9.3 vs. 9.5%, respectively), with no significant differences noted between groups. Improvements in back squat strength were significantly greater for HL compared to LL (19.6 vs. 8.8%, respectively) and there was a trend for greater increases in 1RM bench press (6.5 vs. 2.0%, respectively). Upper body muscle endurance (assessed by the bench press at 50% 1RM to failure) improved to a greater extent in LL compared to HL (16.6% vs. -1.2%, respectively). These findings indicate that both HL and LL training to failure can elicit significant increases in muscle hypertrophy among well-trained young men; however, HL training is superior for maximizing strength adaptations.
Abstract There has been much debate as to optimal loading strategies for maximising the adaptive response to resistance exercise. The purpose of this paper therefore was to conduct a meta-analysis of randomised controlled trials to compare the effects of low-load (≤60% 1 repetition maximum [RM]) versus high-load (≥65% 1 RM) training in enhancing post-exercise muscular adaptations. The strength analysis comprised 251 subjects and 32 effect sizes (ESs), nested within 20 treatment groups and 9 studies. The hypertrophy analysis comprised 191 subjects and 34 ESs, nested with 17 treatment groups and 8 studies. There was a trend for strength outcomes to be greater with high loads compared to low loads (difference = 1.07 ± 0.60; CI: -0.18, 2.32; p = 0.09). The mean ES for low loads was 1.23 ± 0.43 (CI: 0.32, 2.13). The mean ES for high loads was 2.30 ± 0.43 (CI: 1.41, 3.19). There was a trend for hypertrophy outcomes to be greater with high loads compared to low loads (difference = 0.43 ± 0.24; CI: -0.05, 0.92; p = 0.076). The mean ES for low loads was 0.39 ± 0.17 (CI: 0.05, 0.73). The mean ES for high loads was 0.82 ± 0.17 (CI: 0.49, 1.16). In conclusion, training with loads ≤50% 1 RM was found to promote substantial increases in muscle strength and hypertrophy in untrained individuals, but a trend was noted for superiority of heavy loading with respect to these outcome measures with null findings likely attributed to a relatively small number of studies on the topic.
High-intensity interval training (HIIT) has become a promising strategy to induce a number of metabolic adaptations and alter body composition. Recent evidence suggests that HIIT can be a time-efficient strategy to promote health in sedentary overweight/obese individuals. This may be contrary to the belief held by some health professionals that training programs at high intensity are not appropriate for optimizing fat oxidation and inducing weight loss in this population. This paper reviews the results of HIIT studies conducted with overweight/obese individuals. A special focus is on the effect of HIIT on fat oxidation and weight loss.
This paper discusses and challenges the current opinion that exercise adaptation is generally defined by modality; resistance exercise (RE), or aerobic exercise (AE). In presenting a strong body of recent research which demonstrably challenges these perceptions we suggest alternate hypotheses towards physiological adaptation which is hinged more upon the effort than the exercise modality. Practical implications of this interpretation of exercise adaptation might effect change in exercise adherence since existing barriers to exercise of time, costs, specialized equipment, etc. become nullified. In presenting the evidence herein we suggest that lay persons wishing to attain the health and fitness (including strength and muscle hypertrophy) benefits of exercise can choose from a wide range of potential exercise modalities so long as the effort is high. Future research should consider this hypothesis by directly comparing RE and AE for acute responses and chronic adaptations.
Aim:
This study examined low volume resistance training (RT) in trained participants with and without advanced training methods.
Methods:
Trained participants (RT experience 4+3 years) were randomised to groups performing single set RT;; ssRM (n = 21) performing repetitions to self--determined repetition maximum (RM), ssMMF (n = 30) performing repetitions to momentary muscular failure (MMF), and ssRP (n = 28) performing repetitions to self--determined RM using a rest pause (RP) method. Each performed supervised RT 2x/week for 10 weeks. Outcomes included maximal isometric strength and body composition using bioelectrical impedance analysis.
Results:
The ssRM group did not significantly improve in any outcome. The ssMMF and ssRP groups both significantly improved strength (p < 0.05). Magnitude of changes using effect size (ES) was examined between groups. Strength ES's were considered large for ssMMF (0.91 to 1.57) and ranging small to large for ssRP (0.42 to 1.06). Body composition data revealed significant improvements (p < 0.05) in muscle and fat mass and percentages for whole body, upper limbs and trunk for ssMMF, but only upper limbs for ssRP. Body composition ES's ranged moderate to large for ssMMF (0.56 to 1.27) and ranged small to moderate for ssRP (0.28 to 0.52). ssMMF also significantly improved (p < 0.05) total abdominal fat and increased intracellular water with moderate ES's (--0.62 and 0.56 respectively).
Conclusion:
Training to self--determined RM is not efficacious for trained participants. Training to MMF produces greatest improvements in strength and body composition, however, RP style training does offer some benefit.
Growing research suggests that high-intensity interval training (HIIT) is a time-efficient exercise strategy to improve cardiorespiratory and metabolic health. “All out” HIIT models such as Wingate-type exercise are particularly effective, but this type of training may not be safe, tolerable or practical for many individuals. Recent studies, however, have revealed the potential for other models of HIIT, which may be more feasible but are still time-efficient, to stimulate adaptations similar to more demanding low-volume HIIT models and high-volume endurance-type training. As little as 3 HIIT sessions per week, involving ≤10 min of intense exercise within a time commitment of ≤30 min per session, including warm-up, recovery between intervals and cool down, has been shown to improve aerobic capacity, skeletal muscle oxidative capacity, exercise tolerance and markers of disease risk after only a few weeks in both healthy individuals and people with cardiometabolic disorders. Additional research is warranted, as studies conducted have been relatively short-term, with a limited number of measurements performed on small groups of subjects. However, given that “lack of time” remains one of the most commonly cited barriers to regular exercise participation, low-volume HIIT is a time-efficient exercise strategy that warrants consideration by health practitioners and fitness professionals.
The One Repetition Maximum (1-RM) test is commonly used to assess strength. However, direct assessments of 1-RM are time consuming and unsafe for novice lifters. Whilst various equations exist to predict 1-RM, there is limited research on the validity of these equations. The purpose of this study was to assess the validity of using sub-maximal ratings of perceived exertion (RPE) to predict 1-RM in young adults, using the Borg 6-20 RPE Scale. Twenty healthy participants (ten male (Mean ± SD, 20.8 ± 0.6 y, 75.7 ± 9.3 kg, 1.8 ± 0.07 m) and ten female (20.3 ± 0.7 y, 68.4 ± 10.0 kg, 1.68 ± 0.03 m)) completed two trials involving resistance exercises for both the upper and lower body. In the first trial the 1-RM for the bilateral biceps curl (BC) and the bilateral knee extension (KE) were determined for each participant. In the second trial, participants performed blinded repetitions which were equivalent to 20, 40 and 60 % of 1-RM for both exercises. The RPE was recorded immediately after two repetitions had been completed at each intensity. The order of intensity of the repetitions was randomly assigned with participants wearing blindfolds to exclude the possibility of pre-determined judgments about load and RPE. Individual RPE recorded at each intensity was subjected to linear regression analysis and the line of best fit was extrapolated to RPE 20 to predict 1-RM in both exercises. There was no significant difference (p > 0.05) between the 1-RM predicted from RPE 20 and measured 1-RM for both exercises for the men and women. Measured and predicted values for men were 46.0 ± 4.6 and 45.2 ± 6. 1 kg for biceps curl, and 46.3 ± 3.8 and 43.0 ± 7.1 kg for knee extension, respectively. Measured and predicted values for women were 18.6 ± 5.7 and 19.3 ± 5.6 kg for biceps curl, and 25.5 ± 9.6 and 27.2 ± 12.6 kg for knee extension, respectively. Pearson product-moment correlation coefficients between actual and predicted 1-RM for the BC and KE were 0.97 and 0.92, respectively. These results provide evidence that submaximal ratings of perceived exertion can be used to provide reasonably accurate estimates of 1-RM in young and active men and women. Key pointsThe direct measurement of 1-RM is time consuming and impractical for large groups. This has led to the development of prediction models which employ sub-maximal loads in order to minimise the limitations and risks of maximal strength assessment.The principle of using the ratings of perceived exertion from sub-maximal work rates to predict maximal work rate has been established.With the exception of the present study, there are no published studies on the efficacy of using the Borg 6-20 RPE scale for predicting maximal strength.Perceived exertion ratings from the Borg 6-20 Scale may be used to provide reasonably accurate estimates of 1-RM.Sub-maximal exercise intensities in the range of 20 - 60% of the 1-RM can be used estimate the 1-Repetition Maximum for upper and lower body exercise.
It is an undeniable fact that resistance training (RT) is a potent stimulus for muscle hypertrophy and strength gain, but it is less understood whether RT can increase maximal aerobic capacity (VO2max). The purpose of this brief review is to discuss whether or not RT enhances VO2max in young (20–40 years) and older subjects (>60 years). Only 3 of 17 studies involving young subjects have indicated significant increases in VO2max following RT, while six of nine studies in older subjects have reported significant improvements in VO2max following RT. There was a significant negative correlation between the initial VO2max and RT-induced change in VO2max. This result suggests that RT-induced increase in VO2max is dependent upon the subject’s initial VO2max. The RT-induced increase in VO2max may be elicited when their initial relative VO2max is lower than 25 ml/kg/min for older subjects and lower than 40 ml/kg/min for young subjects. Thus, RT can be expected to improve concurrently both muscular and cardiovascular fitnesses within a single mode of RT when young and old persons have initially low fitness levels.
The size principle states that motor units are recruited in an orderly manner from the smaller (lower threshold) to the larger (higher threshold) motor units, and that the recruitment is dependent on the effort of the activity. Greater recruitment produces higher muscular force. However, the pervasive faulty assumption that maximal or near maximal force (very heavy resistance) is required for recruitment of the higher-threshold motor units and optimal strength gains is not supported by the size principle, motor unit activation studies, or resistance training studies. This flawed premise has resulted in the unsubstantiated heavier-is-better recommendation for resistance training. ( J Exerc Sci Fit Vol 6 No 2 67-86 2008)
Research demonstrates resistance training produces significant improvement in cardiovascular fitness (VO 2 max, economy of movement). To date no review article has considered the underlying physiological mechanisms that might support such improvements. This article is a comprehensive, systematic narrative review of the literature surrounding the area of resistance training, cardiovascular fitness and the acute responses and chronic adaptations it produces. The primary concern with existing research is the lack of clarity and inappropriate quantification of resistance training intensity. Thus, an important consideration of this review is the effect of intensity. The acute metabolic and molecular responses to resistance training to momentary muscular failure do not differ from that of traditional endurance training. Myocardial function appears to be maintained, perhaps enhanced, in acute response to high intensity resistance training, and contraction intensity appears to mediate the acute vascular response to resistance training. The results of chronic physiological adaptations demonstrate that resistance training to momentary muscular failure produces a number of physiological adaptations, which may facilitate the observed improvements in cardiovascular fitness. The adaptations may include an increase in mitochondrial enzymes, mitochondrial proliferation, phenotypic conversion from type IIx towards type IIa muscle fibers, and vascular remodeling (including capillarization). Resistance training to momentary muscular failure causes sufficient acute stimuli to produce chronic physiological adaptations that enhance cardiovascular fitness. This review appears to be the first to present this conclusion and, therefore, it may help stimulate a changing paradigm addressing the misnomer of 'cardiovascular' exercise as being determined by modality.
It is known that ambulatory exercises such as brisk walking and jogging are potent stimuli for improving aerobic capacity, but it is less understood whether ambulatory exercise can increase leg muscle size and function. The purpose of this brief review is to discuss whether or not ambulatory exercise elicits leg muscle hypertrophy in older adults. Daily ambulatory activity with moderate (>3 metabolic equivalents [METs], which is defined as the ratio of the work metabolic rate to the resting metabolic rate) intensity estimated by accelerometer is positively correlated with lower body muscle size and function in older adults. Although there is conflicting data on the effects of short-term training, it is possible that relatively long periods of walking, jogging, or intermittent running for over half a year can increase leg muscle size among older adults. In addition, slow-walk training with a combination of leg muscle blood flow restriction elicits muscle hypertrophy only in the blood flow restricted leg muscles. Competitive marathon running and regular high intensity distance running in young and middle-aged adults may not produce leg muscle hypertrophy due to insufficient recovery from the damaging running bout, although there have been no studies that have investigated the effects of running on leg muscle morphology in older subjects. It is clear that skeletal muscle hypertrophy can occur independently of exercise mode and load.
Recently in BJSM, Dr Berkoff1 highlighted some ‘hot topics’ in sports and exercise medicine. A variety of topics were covered, all of which were ‘hot’. Of particular interest, however, was the fact that Dr Berkoff preceded his article with a definition of ‘hot’. Within sports and exercise medicine, and indeed in all scientific disciplines, definitions are of great importance. In fact, “The primary advantage of operational definitions lies in the unification of science and the resolution of controversy.”2 It is the definition and use of a term within a topic that might also be deemed as ‘hot’ that this editorial attempts to address: Intensity in resistance training (RT). Recent publications regarding RT have attempted to offer clarification on the definition of intensity.3 ,4 Fisher and Smith3 wrote regarding the use of the term intensity within RT suggesting that it is better representative of effort, whereas other authors have considered it synonymous with load.4 Fisher and Smith2 are not the first to suggest that the use of intensity to refer to load in RT is inappropriate. Others have previously attempted to instigate a change in the language used by researchers and practitioners.5 ,6 Despite previously finding myself supporting this view (that intensity is better defined as effort and not load) regarding the use of the term and having published as such,6 ,7 further consideration has left me doubting the value of both interpretation of intensity as synonymous with load or effort. Thus, this editorial seeks to ask the readers of BJSM, and the wider community involved in RT, to consider the use of the term intensity as it stands and whether both sides of the disagreement are defending inappropriate idioms. More specifically, however, it …
Background
The benefits of exercise are well established but one major barrier for many is time. It has been proposed that short period resistance training (RT) could play a role in weight control by increasing resting energy expenditure (REE) but the effects of different kinds of RT has not been widely reported.
Methods
We tested the acute effects of high-intensity interval resistance training (HIRT) vs. traditional resistance training (TT) on REE and respiratory ratio (RR) at 22 hours post-exercise. In two separate sessions, seventeen trained males carried out HIRT and TT protocols. The HIRT technique consists of: 6 repetitions, 20 seconds rest, 2/3 repetitions, 20 secs rest, 2/3 repetitions with 2′30″ rest between sets, three exercises for a total of 7 sets. TT consisted of eight exercises of 4 sets of 8–12 repetitions with one/two minutes rest with a total amount of 32 sets. We measured basal REE and RR (TT0 and HIRT0) and 22 hours after the training session (TT22 and HIRT22).
Results
HIRT showed a greater significant increase (p < 0.001) in REE at 22 hours compared to TT (HIRT22 2362 ± 118 Kcal/d vs TT22 1999 ± 88 Kcal/d). RR at HIRT22 was significantly lower (0.798 ± 0.010) compared to both HIRT0 (0.827 ± 0.006) and TT22 (0.822 ± 0.008).
Conclusions
Our data suggest that shorter HIRT sessions may increase REE after exercise to a greater extent than TT and may reduce RR hence improving fat oxidation. The shorter exercise time commitment may help to reduce one major barrier to exercise.
This study tested the hypothesis that chronic aerobic and resistance exercise (AE+RE) would elicit greater muscle hypertrophy than resistance exercise only (RE). Ten men (25±4 yrs) performed 5 wks unilateral knee extensor AE+RE. The opposing limb was subjected to RE. AE completed 6 hrs prior to RE, consisted of ~45 min one-legged cycle ergometry. RE comprised 4 x 7 maximal concentric-eccentric knee extensions. Various indices of in vivo knee extensor function were measured before and after training. Magnetic resonance imaging (MRI) assessed m. quadricep femoris (QF) cross-sectional area (CSA), volume, and signal intensity (SI). Biopsies obtained from m. vastus lateralis determined fiber CSA, enzyme levels and gene expression of myostatin, atrogin-1, MuRF-1, PGC-1α and VEGF. Increases (P < 0.05) in isometric strength and peak power, respectively were comparable in AE+RE (9 and 29%) and RE (11 and 24%). AE+RE showed greater increase (14%; P < 0.05) in QF volume than RE (8%). Muscle fiber CSA increased 17% after AE+RE (P < 0.05) and 9% after RE (P > 0.05). QF SI increased (12%; P < 0.05) after AE+RE, but not RE. Neither AE+RE nor RE showed altered mRNA-levels. Citrate Synthase activity increased (P < 0.05) after AE+RE. The results suggest that the increased aerobic capacity shown with AE+RE, was accompanied by a more robust increase in muscle size compared with RE. While this response was not carried over to greater improvement in muscle function, it remains that intense AE can be executed prior to RE without compromising performance outcome.
HIGH-INTENSITY AEROBIC INTERVAL TRAINING (HIIT) IS A POPULAR STRATEGY FOR IMPROVING CARDIORESPIRATORY FITNESS AND HEALTH, AS WELL AS REDUCING BODY FAT LEVELS. THIS ARTICLE WILL EXPLORE THE BENEFITS OF HIIT AND DISCUSS ITS APPLICATION FOR FITNESS TRAINING.
This investigation examined the influence of the number of repetitions per set on power output and muscle metabolism during leg press exercise. Six trained men (age 34 ± 6 yr) randomly performed either 5 sets of 10 repetitions (10REP), or 10 sets of 5 repetitions (5REP) of bilateral leg press exercise, with the same initial load and rest intervals between sets. Muscle biopsies (vastus lateralis) were taken before the first set, and after the first and the final sets. Compared with 5REP, 10REP resulted in a markedly greater decrease (P<0.05) of the power output, muscle PCr and ATP content, and markedly higher (P<0.05) levels of muscle lactate and IMP. Significant correlations (P<0.01) were observed between changes in muscle PCr and muscle lactate (R(2) = 0.46), between changes in muscle PCr and IMP (R(2) = 0.44) as well as between changes in power output and changes in muscle ATP (R(2) = 0.59) and lactate (R(2) = 0.64) levels. Reducing the number of repetitions per set by 50% causes a lower disruption to the energy balance in the muscle. The correlations suggest that the changes in PCr and muscle lactate mainly occur simultaneously during exercise, whereas IMP only accumulates when PCr levels are low. The decrease in ATP stores may contribute to fatigue.
Resistance training produces an array of health benefits, as well as the potential to promote muscular adaptations of strength, size, power and endurance. The American College of Sports Medicine (ACSM) regularly publish a position stand making recommendations for optimal achievement of the desired training goals. However, the most recent position stand (as well as previous ones) has come under heavy criticism for misrepresentation of research, lack of evidence and author bias. Therefore this paper proposes a set of scientifically rigorous resistance training guidelines, reviewing and summarising the relevant research for the purpose of proposing more logical, evidence-based training advice. We recommend that appreciably the same muscular strength and endurance adaptations can be attained by perform-ing a single set of ~8-12 repetitions to momentary muscular failure, at a repetition duration that maintains muscular tension throughout the entire range of motion, for most major muscle groups once or twice each week. All resistance types (e.g. free-weights, resistance machines, bodyweight, etc.) show potential for increases in strength, with no significant difference between them, although resistance machines appear to pose a lower risk of injury. There is a lack of evidence to suggest that balance from free weights or use of unstable surfaces shows any transfer-ence to sporting improvement, and explosive movements are also not recommended as they present a high injury risk and no greater benefit than slow, controlled weight training. Finally, we consider genetic factors in relation to body type and growth potential.
2002;5(3):54-59. The purpose of this investigation was to determine if 1-RM strength could be predicted from a 4-6 RM submaximal strength test with a greater accuracy than the commonly used 7-10 submaximal strength test. Thirty-four healthy males between the ages of 19 and 32 participated in this study. Subjects completed 1-RM, 4-6 RM, and 7-10 RM strength assessments in random order with a minimum of 48 hours between each strength assessment. During each session, subjects performed strength assessments for the bench press, incline press, triceps extension, biceps curl, and leg extension. Multiple regression analysis was used to produce equations for predicting 1-RM strength from 4 to 6 or 7 to 10 repetition maximum tests. The 4-6 RM prediction equations improved the predictive accuracy of 1-RM strength compared to the 7-10 RM prediction equations based on the adjusted R 2 and standard error of estimate. Since no injuries or symptoms of delayed onset of muscle soreness were reported during either the 7-10 RM or the 4-6 RM submaximal strength assessments, the results of this study indicate that when attempting to predict 1-RM strength in healthy, young, males, a 4-6 RM submaximal strength assessment appears to be the more accurate test.
The primary objective of this investigation was to identify which components of endurance training (e.g., modality, duration, frequency) are detrimental to resistance training outcomes. A meta-analysis of 21 studies was performed with a total of 422 effect sizes (ESs). Criteria for the study included were (a) compare strength training alone to strength plus endurance training (concurrent) or to compare combinations of concurrent training; (b) the outcome measures include at least one measure of strength, power, or hypertrophy; and (c) the data necessary to calculate ESs must be included or available. The mean ES for hypertrophy for strength training was 1.23; for endurance training, it was 0.27; and for concurrent training, it was 0.85, with strength and concurrent training being significantly greater than endurance training only. The mean ES for strength development for strength training was 1.76; for endurance training, it was 0.78; and for concurrent training, it was 1.44. Strength and concurrent training was significantly greater than endurance training. The mean ES for power development for strength training only was 0.91; for endurance training, it was 0.11; and for concurrent training, it was 0.55. Significant differences were found between all the 3 groups. For moderator variables, resistance training concurrently with running, but not cycling, resulted in significant decrements in both hypertrophy and strength. Correlational analysis identified significant negative relationships between frequency (-0.26 to -0.35) and duration (-0.29 to -0.75) of endurance training for hypertrophy, strength, and power. Significant relationships (p < 0.05) between ES for decreased body fat and % maximal heart rate (r = -0.60) were also found. Our results indicate that interference effects of endurance training are a factor of the modality, frequency, and duration of the endurance training selected.
This study describes the results of a survey of the strength and conditioning practices of strongman competitors. A 65-item online survey was completed by 167 strongman competitors. The subject group included 83 local, 65 national, and 19 international strongman competitors. The survey comprised 3 main areas of enquiry: (a) exercise selection, (b) training protocols and organization, and (c) strongman event training. The back squat and conventional deadlift were reported as the most commonly used squat and deadlift (65.8 and 88.0%, respectively). Eighty percent of the subjects incorporated some form of periodization in their training. Seventy-four percent of subjects included hypertrophy training, 97% included maximal strength training, and 90% included power training in their training organization. The majority performed speed repetitions with submaximal loads in the squat and deadlift (59.9 and 61.1%, respectively). Fifty-four percent of subjects incorporated lower body plyometrics into their training, and 88% of the strongman competitors reported performing Olympic lifts as part of their strongman training. Seventy-eight percent of subjects reported that the clean was the most performed Olympic lift used in their training. Results revealed that 56 and 38% of the strongman competitors used elastic bands and chains in their training, respectively. The findings demonstrate that strongman competitors incorporate a variety of strength and conditioning practices that are focused on increasing muscular size, and the development of maximal strength and power into their conditioning preparation. The farmers walk, log press, and stones were the most commonly performed strongman exercises used in a general strongman training session by these athletes. These data provide information on the training practices required to compete in the sport of strongman.
One possible reason for the continued neglect of statistical power analysis in research in the behavioral sciences is the inaccessibility of or difficulty with the standard material. A convenient, although not comprehensive, presentation of required sample sizes is provided. Effect-size indexes and conventional values for these are given for operationally defined small, medium, and large effects. The sample sizes necessary for .80 power to detect effects at these levels are tabled for 8 standard statistical tests: (1) the difference between independent means, (2) the significance of a product-moment correlation, (3) the difference between independent rs, (4) the sign test, (5) the difference between independent proportions, (6) chi-square tests for goodness of fit and contingency tables, (7) 1-way analysis of variance (ANOVA), and (8) the significance of a multiple or multiple partial correlation.
The present study tested, both retrospectively and prospectively, exercise-induced mood changes among regular exercisers. Specifically, it examined the extent to which preferred exercise modality promoted greater mood benefits. A group of 25 exercise participants (M = 35.5 yr., SD = 10.5 yr.) took part in the study. All participants had exercised at least three times a week (M = 3.5, SD = 2.3) during the previous year. Participants completed a 14-item Exercise Preference Questionnaire to provide retrospective evaluations of their most- and least-preferred type of exercise. For the prospective investigation, participants completed the Brunel Mood Scale (BRUMS) 15 minutes before and immediately after their most- and least-preferred exercise sessions. One week separated completion of each exercise session. Retrospective assessment of exercise-induced mood changes showed strong support for enhanced mood following the preferred mode of exercise. Also, as hypothesized, prospective results showed that mood enhancement was greater following the preferred exercise modality, but significant mood enhancement also occurred following the least-preferred modality among experienced exercisers. In conclusions, findings support the principle that exercise can provide psychological benefits to its participants, in the form of positive affective outcomes, something that appears to be enhanced by preferred exercise modality. Given the important public health implications of exercise adherence, future research should seek to further investigate the mechanisms of exercise-induced mood enhancement
AMP-activated protein kinase (AMPK) has been extensively studied in whole muscle biopsy samples of humans, yet the fiber type-specific expression and/or activation of AMPK is unknown. We examined basal and exercise AMPK-alpha Thr(172) phosphorylation and AMPK subunit expression (alpha(1), alpha(2), and gamma(3)) in type I, IIa, and IIx fibers of human skeletal muscle before and after 10 days of exercise training. Before training basal AMPK phosphorylation was greatest in type IIa fibers (P < 0.05 vs. type I and IIx), while an acute bout of exercise increased AMPK phosphorylation in all fibers (P < 0.05), with the greatest increase occurring in type IIx fibers. Exercise training significantly increased basal AMPK phosphorylation in all fibers, and the exercise-induced increases were uniformly suppressed compared with pretraining exercise. Expression of AMPK-alpha(1) and -alpha(2) was similar between fibers and was not altered by exercise training. However, AMPK-gamma(3) was differentially expressed in skeletal muscle fibers (type IIx > type IIa > type I), irrespective of training status. Thus skeletal muscle AMPK phosphorylation and AMPK expression are fiber type specific in humans in the basal state, as well as during exercise. Our findings reveal fiber type-specific differences that have been masked in previous studies examining mixed muscle samples.
The quadriceps femoris muscles of seven men were electrically stimulated under extended anaerobic conditions to quantitate anaerobic energy release and the contribution of the glycolytic system to total ATP production. Muscles were intermittently stimulated 64 times at 20 Hz while leg blood flow was occluded. Each contraction lasted 1.6 s and was followed by 1.6 s of rest. The total contraction time was 102.4 s. Muscle biopsies were taken at rest and following 16, 32, 48, and 64 contractions. The ATP turnover rates during the four 16-contraction periods were 6.12, 2.56, 2.17, and 0.64 mmol X kg dry muscle-1 X s-1 contraction time. Glycolysis provided 58%, phosphocreatine 40% and a decreased ATP store 2% of the consumed energy during the initial 16 contractions. Glycolysis was responsible for 90% of the total ATP production beyond contraction 16. Absolute glycolytic ATP production decreased to 60, 55, and 17% of the amount in the initial 16 contractions during the final three periods, respectively. In conclusion glycolysis produced approximately 195 mmol ATP/kg dry muscle during the initial 48 contractions (76.8 s) and only approximately 15 mmol ATP/kg dry muscle during the final 16 contractions. Equivalent values for total ATP turnover were 278 and 16.5 mmol/kg dry muscle.
We reported, using a unilateral resistance training (RT) model, that training with high or low loads (mass per repetition) resulted in similar muscle hypertrophy and strength improvements in RT-naïve subjects. Here we aimed to determine whether the same was true in men with previous RT experience using a whole-body RT program and whether post-exercise systemic hormone concentrations were related to changes in hypertrophy and strength. Forty-nine resistance-trained men (mean ± SEM, 23 ± 1 y) performed 12 wk of whole-body RT. Subjects were randomly allocated into a higher-repetition (HR) group who lifted loads of ~30-50% of their maximal strength (1RM) for 20-25 repetitions/set (n=24) or a lower-repetition (LR) group (~75-90% 1RM, 8-12 repetitions/set, n=25), with all sets being performed to volitional failure. Skeletal muscle biopsies, strength testing, DXA scans, and acute changes in systemic hormone concentrations were examined pre- and post-training. In response to RT, 1RM strength increased for all exercises in both groups (p < 0.01), with only the change in bench press being significantly different between groups (HR: 9 ± 1 vs. LR: 14 ±1 kg, p = 0.012). Fat- and bone-free (lean) body mass, type I and type II muscle fibre cross sectional area increased following training (p < 0.01) with no significant differences between groups. No significant correlations between the acute post-exercise rise in any purported anabolic hormone and the change in strength or hypertrophy were found. In congruence with our previous work, acute post-exercise systemic hormonal rises are not related to or in any way indicative of RT-mediated gains in muscle mass or strength. Our data show that in resistance-trained individuals load, when exercises are performed to volitional failure, does not dictate hypertrophy or, for the most part, strength gains.
This paper reviews the existing evidence for the potential contribution of metabolic and mechanical stimuli to muscle growth in response to a variety of exercise modalities and intensities. Recent research has demonstrated that low-load resistance training can elicit comparable hypertrophy to that of high-load resistance training when each set is performed until failure. The degree of metabolic fatigue would be greater for resistance training with lower loads compared to higher loads at the point of muscle failure, which may compensate for the lower mechanical stress. This may also explain why muscle hypertrophy occurs to varying magnitudes when activities such as cycling and walking are performed. Furthermore, the application of blood flow restriction to the working muscles during these activities induces greater hypertrophy albeit at the same level of mechanical stress, which would suggest a possible contribution from metabolic stress. Thus, it is plausible that both mechanical and metabolic stimuli are primary mechanisms for muscle hypertrophy and the degree of contributions of both stimuli determines the exercise-induced muscle hypertrophy.
Cycle training is widely performed as a major part of any exercise program seeking to improve aerobic capacity and cardiovascular health. However, the effect of cycle training on muscle size and strength gain still requires further insight, even though it is known that professional cyclists display larger muscle size compared to controls. Therefore, the purpose of this review is to discuss the effects of cycle training on muscle size and strength of the lower extremity and the possible mechanisms for increasing muscle size with cycle training. It is plausible that cycle training requires a longer period to significantly increase muscle size compared to typical resistance training due to a much slower hypertrophy rate. Cycle training induces muscle hypertrophy similarly between young and older age groups, while strength gain seems to favor older adults, which suggests that the probability for improving in muscle quality appears to be higher in older adults compared to young adults. For young adults, higher-intensity intermittent cycling may be required to achieve strength gains. It also appears that muscle hypertrophy induced by cycle training results from the positive changes in muscle protein net balance.
Objective: The purpose of this study was to identify the influence of readiness of change for physi- cal activity (PA), sociodemographic factors, lifestyle and physical activity status (PAS) on per- ceived barriers among Spanish university students. Participants: Seven hundred and seventy two (n = 772) men and women ages 17 - 39 at a north-west regional university in Spain participated in the study. Methods: The International Physical Activity Questionnaire, the States of Change for Physical Activity Behaviour Questionnaire and the Self-perceived Barriers for Physical Activity Questionnaire were used. Description, correlation and multiple regression analyses were com- pleted. Results: Participants self-perceived low average-score barriers (2.6 ± 1.4 over 10.0). The 3-higher scores barriers corresponded to “too much work”; “lack of time for exercise” and “lazi- ness”. Gender, PAS and self-perceived health were shown to be associated with perceived barriers. Conclusions: University institutions should consider those factors that predict barriers to PA to develop effective intervention programs.
Physical exercise capacity has been shown to predict cardiovascular disease incidence and is increasingly measured in epidemiological studies. However, direct measurement of peak oxygen uptake is too time consuming in large-scale studies. We therefore investigated whether a brief 3-minute step-test protocol can be used to estimate peak oxygen uptake in these settings.
A group of 97 subjects performed the YMCA step test and a maximal treadmill test with continuous measurement of oxygen uptake. Correlation and linear regression analyses were used to identify VO2peak predictors obtained from the step test and to develop models for VO2peak estimation.
The YMCA model, including the 1-minute heart beat count, predicted VO2peak with R = 0.83. A novel simplified model based on the heart rate at 45 s of recovery performed comparable (R = 0.83). However, models based on heart rate measures were only valid in subjects who completed the test according to protocol, but not in subjects who terminated prematurely. For the applicability in subjects with low exercise capacity, a new model including gas exchange analysis enabled prediction of VO2peak (R = 0.89). All models were validated in an independent sample (r = 0.86-0.91). Exercise time of the step test was less than one-hird of standard ergospirometry (treadmill test: 654 ± 151 s, step test: 180 s, p < 0.001).
In large-scale epidemiological studies with limited time slots for exercise testing and significant proportions of subjects with low exercise capacity a modified version of the YMCA step test may be used to predict VO2peak.
Current dogma suggests aerobic exercise training has minimal effect on skeletal muscle size. We and others have demonstrated that aerobic exercise acutely and chronically alters protein metabolism and induces skeletal muscle hypertrophy. These findings promote an antithesis to the status quo by providing novel perspective on skeletal muscle mass regulation and insight into exercise-countermeasures for populations prone to muscle loss.
Although not commonly associated with gains in skeletal muscle mass, aerobic exercise stimulates muscle protein synthesis and skeletal muscle hypertrophy.
Walking combined with blood flow reduction (BFR-walk) elicits muscle hypertrophy. However, the skeletal muscle intracellular signaling behind this response is currently unknown.
To investigate the effects of BFR-walk on mechanistic target of rapamycin (mTOR) and mitogen-activated protein kinase (MAPK) signaling pathways in young men.
Six young men performed 20 minutes of treadmill walking at 55 % of their predetermined maximum oxygen uptake. A pressure cuff belt was applied to the most proximal thigh of only one leg (BFR-Leg, external compression was 240 mmHg) whereas the other leg (CON-Leg) was without BFR during walking. Muscle biopsies were taken from the vastus lateralis of the CON-Leg before exercise and in both legs 3 hours after exercise.
Erk1/2 phosphorylation levels were significantly (p<0.05) increased after exercise in both legs, however, only the BFR-Leg saw an increased phosphorylation of p38. For mTOR signaling, there were no changes in Akt, mTOR, or S6K1 phosphorylation levels before or after walking. However, eEF2 phosphorylation level was significantly (p<0.05) lower for the BFR-Leg 3 hours after walking compared with CON-Leg.
BFR-walk exercise may activate some intracellular signaling cascades that are associated with muscle hypertrophy in young men. This article is protected by copyright. All rights reserved.
The activity pattern of low-threshold human trapezius motor units was examined in response to brief, voluntary increases in contraction amplitude ('EMG pulse') superimposed on a constant contraction at 4-7 % of the surface electromyographic (EMG) response at maximal voluntary contraction (4-7 % EMGmax). EMG pulses at 15-20 % EMGmax were superimposed every minute on contractions of 5, 10, or 30 min duration. A quadrifilar fine-wire electrode recorded single motor unit activity and a surface electrode recorded simultaneously the surface EMG signal. Low-threshold motor units recruited at the start of the contraction were observed to stop firing while motor units of higher recruitment threshold stayed active. Derecruitment of a motor unit coincided with the end of an EMG pulse. The lowest-threshold motor units showed only brief silent periods. Some motor units with recruitment threshold up to 5 % EMGmax higher than the constant contraction level were recruited during an EMG pulse and kept firing throughout the contraction. Following an EMG pulse, there was a marked reduction in motor unit firing rates upon return of the surface EMG signal to the constant contraction level, outlasting the EMG pulse by 4 s on average. The reduction in firing rates may serve as a trigger to induce derecruitment. We speculate that the silent periods following derecruitment may be due to deactivation of non-inactivating inward current ('plateau potentials'). The firing behaviour of trapezius motor units in these experiments may thus illustrate a mechanism and a control strategy to reduce fatigue of motor units with sustained activity patterns.
The physical requirements for women soccer players appear to be similar to those for men, with high levels of aerobic capacity, sprint speed and recovery being fundamental for success (Krustrup et al. Med Sci Sports Exerc 37: 1242-1248, 2005). Specific interventions designed to improve training status in male soccer players have been assessed in several previous studies (e.g. Hoff et al. Br J Sports Med 36: 218-221, 2001). However, to our knowledge only one study has examined the responses to training interventions in female players (Polman et al. J Sports Sci 22: 191-203, 2004) and the most effective method remains to be determined.
PURPOSE: To examine the effects of three training interventions on the aerobic and anaerobic capacity of collegiate level female soccer players. METHODS: The aerobic and anaerobic capacities of 23 members of an NAIA division 1 soccer program were assessed pre- and post-training by a 20m multi-stage fitness test and a 5m multiple shuttle test (Boddington et al. J Sports Sci 19: 223-228, 2001). Participants were matched for aerobic capacity and assigned to one of three training groups, and trained twice per week for 4 weeks. One group participated in a novel high intensity interval training (HIIT) intervention consisting of a series of 30 s shuttle runs at speeds above the velocity at aerobic capacity, interspersed with 30 s periods of rest. The second group completed interval training (IT) consisting of 4 bouts of 4 min running at 90-95% maximum heart rate followed by a 3 min rest period. The final group completed continuous training (CT) involving a continuous 28 min run at 70-80% maximum heart rate. RESULTS: Aerobic capacity increased significantly in both the HIIT and IT groups (mean ± s.d: HIIT: 10.2 ± 4.5%; p < 0.001, IT: 6.1 ± 2.5%; p < 0.01) and increased by a small but non-significant amount in the CT group (3.8 ± 4.6%; p = 0.19) The distance covered during the anaerobic performance test increased in all groups, but only significantly in the HIIT group (HIIT: 31 ± 19 m; p < 0.01, IT: 14 ± 23 m; p = 0.26, CT: 13 ± 23 m; p = 0.34). CONCLUSION: The novel HIIT intervention results in significant increases in both aerobic and anaerobic capacity and therefore appears to be an effective method of fitness training for female soccer players.
The purpose of this study was to examine the effects of a crossfit-based high intensity power training (HIPT) program on aerobic fitness and body composition. Healthy subjects of both genders (23 males, 20 females) spanning all levels of aerobic fitness and body composition completed 10 weeks of HIPT consisting of lifts such as the squat, deadlift, clean, snatch, and overhead press performed as quickly as possible. Additionally, this crossfit-based HIPT program included skill work for the improvement of traditional Olympic lifts and selected gymnastic exercises. Body fat percentage was estimated using whole body plethysmography and maximal aerobic capacity (VO2max) was measured by analyzing expired gasses during a Bruce protocol maximal graded treadmill test. These variables were measured again following 10 weeks of training and compared for significant changes using a paired t-test. Results showed significant (P<0.05) improvements of VO2max in males (43.10±1.40 to 48.96±1.42 ml/kg/min) and females (35.98±1.60 to 40.22±1.62 ml/kg/min) as well as decreased body fat percentage in males (22.2±1.3 to 18.0±1.3) and females (26.6±2.0 to 23.2±2.0). These improvements were significant across all levels of initial fitness. Significant correlations between absolute oxygen consumption and oxygen consumption relative to body weight was found in both men (r=0.83, P<0.001) and women (r=0.94, P<0.001), indicating HIPT improved VO2max scaled to body weight independent of changes to body composition. Our data shows that HIPT significantly improves VO2max and body composition in subjects of both genders across all levels of fitness.
During a set of resistance exercise performed until exhaustion, the relationship between intensity and the number of repetitions can be affected by lifting speed, with faster speeds producing higher numbers. The hypothesized mechanisms include enhanced utilization of the stretch-shortening cycle. This study investigated muscle activations under varying speeds and intensities during bench press using surface electromyography (EMG) to suggest further mechanisms for the above finding. Thirteen weight-trained men (21.7 ± 3.6-year-old) performed bench press until fatigue under five intensities (40-80% 1RM), and four speeds (slow 5.6-s/repetition, medium 2.8-s/repetition, fast 1.9-s/repetition, and ballistic maximum speed). Surface EMG was recorded from the pectoralis, deltoid, and triceps for root-mean-square amplitude and median frequency. EMG amplitudes were greater for faster and heavier conditions before fatigue. Faster conditions, however, produced a significant fall in amplitude during the final concentric phase compared to slower movements. After fatigue, EMG amplitude increased, with the speed effect being maintained. The intensity effect on amplitude either disappeared or remained similar, depending on the muscles. Median frequencies before fatigue were similar among speeds and intensities. The fall in frequency after fatigue was similar across speeds, but greater for lighter intensities. It was concluded that reduced muscle activation during the final concentric phase in faster conditions allowed a better muscle pump, explaining the increased repetition numbers. Fatigue levels are likely to have been similar across speeds, but greater for lower intensities. An incomplete rise in EMG amplitude after fatigue for lower intensities could imply an increased contribution of central fatigue or neuromuscular transmission failure.
Various aspects of neuromuscular, anaerobic, and aerobic performance capacity were investigated in four powerlifters, seven bodybuilders, and three wrestlers with a history of specific training for several years. The data (means ± SD) showed that the three subject groups possessed similar values for maximal isometric force per unit bodyweight (50.7±9.6, 49.3±4.1, and 49.3±10.9 N/kg, respectively).
However, significant (P<0.05) differences were observed in the times for isometric force production, so that e.g., times to produce a 30% force level were shorter for the wrestlers and bodybuilders (28.3±3.1 and 26.4±6.6 ms) than that (53.3±23.7 ms) for the powerlifters. Utilization of elastic energy by the wrestlers was significantly (P<0.05) better than that of the other two subject groups, as judged from differences between the counter-movement and squat jumps at 0, 40, and 100 kg's loads. No differences were observed between the groups in anaerobic power in a 1-min maximal test, but the values for max were higher (P<0.05) among the wrestlers and bodybuilders (57.8±6.6 and 50.8±6.8 ml·kg−1·min−1) as compared to the powerlifters (41.9±7.2 ml ·kg−1·min−1). Within the limitations of the subject sample, no differences of a statistical significancy were observed between the groups in fibre distribution, fibre areas, or the area ratio of fast (FT) and slow (ST) twitch fibres in vastus lateralis. In all subjects the vertical jumping height was positively (P<0.01) correlated with the FT fibre distribution, and negatively with the time of isometric force production (P<0.05). Maximal force was correlated (P<0.001) with thigh girth. Muscle cross-sectional area did not correlate with mean fibre area. It was assumed that the selected aspects of neuromuscular, anaerobic, and aerobic performance capacity may be influenced by muscle structure, but also specifically and/or simultaneously by training lasting for several years.