Higher Training Frequency Is Important for Gaining Muscular Strength Under Volume-Matched Training

Pedal cadence does not affect muscle damage to eccentric cycling performed at similar mechanical work

Purpose: This study aimed to investigate muscle damage when performing equal mechanical work of fast and slow pedaling speed by eccentric muscle actions (ECCs) cycling.

Methods: Nineteen young men [mean ± standard deviation (SD) age: 21.0 ± 2.2 years; height: 172.7 ± 5.9 cm; and body mass: 70.2 ± 10.5 kg] performed maximal effort of ECCs cycling exercise with fast speed (Fast) and slow speed trials (Slow). First, subjects performed the Fast for 5 min by one leg. Second, Slow performed until the total mechanical work was equal to that generated during Fast other one leg. Changes in maximal voluntary isometric contraction (MVC) torque of knee extension, isokinetic pedaling peak torque (IPT), range of motion (ROM), muscle soreness, thigh circumference, muscle echo intensity, and muscle stiffness were assessed before exercise, and immediately after exercise, and 1 and 4 days after exercise.

Results: Exercise time was observed in the Slow (1422.0 ± 330.0 s) longer than Fast (300.0 ± 0.0 s). However, a significant difference was not observed in total work (Fast:214.8 ± 42.4 J/kg, Slow: 214.3 ± 42.2 J/kg). A significant interaction effect was not observed in peak values of MVC torque (Fast:1.7 ± 0.4 Nm/kg, Slow: 1.8 ± 0.5 Nm/kg), IPT, muscle soreness (Fast:4.3 ± 1.6 cm, Slow: 4.7 ± 2.9 cm). In addition, ROM, circumference, muscle thickness, muscle echo intensity, and muscle stiffness also showed no significant interaction.

Conclusion: The magnitude of muscle damage is similar for ECCs cycling with equal work regardless of velocity.

Microdosing Sprint Distribution as an Alternative to Achieve Better Sprint Performance in Field Hockey Players

Introduction: The implementation of optimal sprint training volume is a relevant component of team sport performance. This study aimed to compare the efficiency and effectiveness of two different configurations of within-season training load distribution on sprint performance over 6 weeks. Methods: Twenty male professional FH players participated in the study. Players were conveniently assigned to two groups: the experimental group (MG; n = 11; applying the microdosing training methodology) and the control group (TG; n = 9; traditional training, with players being selected by the national team). Sprint performance was evaluated through 20 m sprint time (T20) m and horizontal force−velocity profile (HFVP) tests before (Pre) and after (Post) intervention. Both measurements were separated by a period of 6 weeks. The specific sprint training program was performed for each group (for vs. two weekly sessions for MG and TG, respectively) attempting to influence the full spectrum of the F-V relationship. Results: Conditional demands analysis (matches and training sessions) showed no significant differences between the groups during the intervention period (p > 0.05). No significant between-group differences were found at Pre or Post for any sprint-related performance (p > 0.05). Nevertheless, intra-group analysis revealed significant differences in F0, Pmax, RFmean at 10 m and every achieved time for distances ranging from 5 to 25 m for MG (p < 0.05). Such changes in mechanical capabilities and sprint performance were characterized by an increase in stride length and a decrease in stride frequency during the maximal velocity phase (p < 0.05). Conclusion: Implementing strategies such as microdosed training load distribution appears to be an effective and efficient alternative for sprint training in team sports such as hockey.

Effects of Different Long-Term Exercise Modalities on Tissue Stiffness

Stiffness is a fundamental property of living tissues, which may be modified by pathologies or traumatic events but also by nutritional, pharmacological and exercise interventions. This review aimed to understand if specific forms of exercise are able to determine specific forms of tissue stiffness adaptations. A literature search was performed on PubMed, Scopus and Web of Science databases to identify manuscripts addressing adaptations of tissue stiffness as a consequence of long-term exercise. Muscular, connective, peripheral nerve and arterial stiffness were considered for the purpose of this review. Resistance training, aerobic training, plyometric training and stretching were retrieved as exercise modalities responsible for tissue stiffness adaptations. Differences were observed related to each specific modality. When exercise was applied to pathological cohorts (i.e. tendinopathy or hypertension), stiffness changed towards a physiological condition. Exercise interventions are able to determine tissue stiffness adaptations. These should be considered for specific exercise prescriptions. Future studies should concentrate on identifying the effects of exercise on the stiffness of specific tissues in a broader spectrum of pathological populations, in which a tendency for increased stiffness is observed.

Effect of different training frequencies on maximal strength performance and muscle hypertrophy in trained individuals-a within-subject design

Several studies comparing resistance training (RT) frequencies may have been affected by the large between-subject variability. This study aimed to compare the changes in lower limbs maximal dynamic strength (1RM) and quadriceps femoris cross-sectional area (CSA) after a RT with different weekly frequencies in strength-trained individuals using a within-subject design. Twenty-four men participated in a 9-week RT program, being randomly divided into two conditions: resistance training with equalized total training volume (RTEV) and with unequalized total training volume (RTUV). The RT protocol used the unilateral leg press 45° exercise and each subject’s lower limb executed one of the proposed frequencies (one and three times/week). All conditions effectively increased 1RM and CSA (p<0.001); however, no significant differences were observed in the values of 1RM (p = 0.454) and CSA (p = 0.310) between the RT frequencies in the RTEV and RTUV conditions. Therefore, RT performed three times a week showed similar increases in 1RM and CSA to the program performed once a week, regardless of training volume equalization. Nevertheless, when the higher RT frequency allowed the application of a greater TTV (i.e., RTUV), higher effect size (ES) values (0.51 and 0.63, 1RM and CSA, respectively) were observed for the adaptations.

Effectiveness comparison of inpatient vs. outpatient pulmonary rehabilitation: a systematic review

Background

Pulmonary rehabilitation (PR) is the cornerstone of nonpharmacological treatments in chronic respiratory disease (CRD) management. PR can be performed in different settings, the most frequent of which are inpatient (inPR) and outpatient (outPR) management. In the literature, these two distinct modalities are generally considered to be the same intervention. Yet, they differ in terms of the length of stay, social support, and the time the patient is not in their normal environment, and the presumed absence of differences in terms of efficacy has never been established.

Purpose

To identify studies that directly compared the effects of inPR and outPR on patients with all types of CRDs through a systematic review and to synthesize the evidence regarding the effectiveness comparison of both modalities.

Methods

A literature search was performed on PubMed, Web of Science, and Cochrane Library on 24 March 2022. The inclusion criteria were: articles with adults with chronic respiratory disease and comparing inPR versus outPR in at least one PR outcome.

Results

Seven hundred thirty-six articles were retrieved from the databases. Six retrospective articles met the inclusion criteria. A best-evidence synthesis (BES) was carried out. Eight outcomes could be found in the included papers. For healthcare burden and refusals, no data could be extracted, and thus no BES was performed. For the eight remaining outcomes, two results were in favor of inPR with moderate evidence (HRQoL and psychological status), three were in favor of no difference between inPR and outPR with moderate or limited evidence (muscle strength, dropouts/adherence, and survival status), and three led to conflicting results (exercise tolerance, dyspnea, and economic costs).

Conclusion

With the current state of knowledge, the majority of the studies converge towards an absence of differences between inPR and outPR or in favor of inPR for seven out of eight outcomes, albeit with moderate, limited, or conflicting evidence. The greater effectiveness of inPR for some outcomes will have to be confirmed in a well-designed RCT in order to orient public health policies in terms of the development of PR with the best evidence-based medicine approach.

Trial registration

PROSPERO: CRD42020166546.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-022-08345-z.

The effect of phasic versus combined neuromuscular electrical stimulation using the StimaWELL 120MTRS system on multifidus muscle morphology and function in patients with chronic low back pain: a randomized controlled trial protocol

Background

Neuromuscular electrical stimulation (NMES) is used to improve muscle strength clinically when rehabilitating various musculoskeletal disorders. However, the effects of NMES on muscle morphology and function in individuals with non-specific chronic low back pain (CLBP) have scarcely been investigated. Although research links deficits in the paraspinal musculature with subjective reports of pain and disability, it is unknown if treatment with NMES can help reverse these deficits. Therefore, the primary aim of this study is to compare the effects of two muscle therapy protocols with a medium-frequency electrotherapy device (the StimaWELL 120MTRS system) on multifidus muscle morphology and function in CLBP patients. The secondary aims are to determine the effects of these protocols subjective reports of pain intensity, pain interference, disability, and catastrophizing.

Methods

A total of 30 participants with non-specific CLBP, aged 18–60, will be recruited from local orthopedic clinics and databases. Participants will be randomized (1:1) to either the phasic or combined (phasic + tonic) muscle therapy protocols on the StimaWELL 120MTRS system. Participants will undergo 20 supervised electrotherapy treatments over a 10-week period. The primary outcomes will be multifidus morphology (e.g. cross-sectional area (CSA), fat infiltration) and function (e.g., contraction measured via %thickness change from a rested to contracted state, and stiffness at rest and during contraction). Secondary outcomes will include pain intensity, interference, disability, and catastrophizing. Both primary and secondary outcomes will be obtained at baseline and at 11-weeks; secondary outcomes measured via questionnaires will also be obtained at 6-weeks, while LBP intensity will be measured before and after each treatment. Paired t-tests will be used to assess within-group changes for all primary outcome measures. A two-way repeated-measures analysis of variance will be used to assess changes in secondary outcomes over time.

Discussion

The results of this trial will help clarify the role of medium-frequency NMES on lumbar multifidus morphology and function.

Trial Registration

NCT04891692, registered retrospectively on May 18, 2021.

State of Knowledge on Molecular Adaptations to Exercise in Humans: Historical Perspectives and Future Directions

For centuries, regular exercise has been acknowledged as a potent stimulus to promote, maintain, and restore healthy functioning of nearly every physiological system of the human body. With advancing understanding of the complexity of human physiology, continually evolving methodological possibilities, and an increasingly dire public health situation, the study of exercise as a preventative or therapeutic treatment has never been more interdisciplinary, or more impactful. During the early stages of the NIH Common Fund Molecular Transducers of Physical Activity Consortium (MoTrPAC) Initiative, the field is well-positioned to build substantially upon the existing understanding of the mechanisms underlying benefits associated with exercise. Thus, we present a comprehensive body of the knowledge detailing the current literature basis surrounding the molecular adaptations to exercise in humans to provide a view of the state of the field at this critical juncture, as well as a resource for scientists bringing external expertise to the field of exercise physiology. In reviewing current literature related to molecular and cellular processes underlying exercise-induced benefits and adaptations, we also draw attention to existing knowledge gaps warranting continued research effort. © 2021 American Physiological Society. Compr Physiol 12:3193-3279, 2022.

Comparison of Weightlifting, Traditional Resistance Training and Plyometrics on Strength, Power and Speed: A Systematic Review with Meta-Analysis

Background

Weightlifting training (WLT) is commonly used to improve strength, power and speed in athletes. However, to date, WLT studies have either not compared training effects against those of other training methods, or been limited by small sample sizes, which are issues that can be resolved by pooling studies in a meta-analysis. Therefore, the objective of this systematic review with meta-analysis was to evaluate the effects of WLT compared with traditional resistance training (TRT), plyometric training (PLYO) and/or control (CON) on strength, power and speed.

Methods

The systematic review included peer-reviewed articles that employed a WLT intervention, a comparison group (i.e. TRT, PLYO, CON), and a measure of strength, power and/or speed. Means and standard deviations of outcomes were converted to Hedges’ g effect sizes using an inverse variance random-effects model to generate a weighted mean effect size (ES).

Results

Sixteen studies were included in the analysis, comprising 427 participants. Data indicated that when compared with TRT, WLT resulted in greater improvements in weightlifting load lifted (4 studies, p = 0.02, g = 1.35; 95% CI 0.20–2.51) and countermovement jump (CMJ) height (9 studies, p = 0.00, g = 0.95; 95% CI 0.04–1.87). There was also a large effect in terms of linear sprint speed (4 studies, p = 0.13, g = 1.04; 95% CI − 0.03 to 2.39) and change of direction speed (CODS) (2 studies, p = 0.36, g = 1.21; 95% CI − 1.41 to 3.83); however, this was not significant. Interpretation of these findings should acknowledge the high heterogeneity across the included studies and potential risk of bias. WLT and PLYO resulted in similar improvements in speed, power and strength as demonstrated by negligible to moderate, non-significant effects in favour of WLT for improvements in linear sprint speed (4 studies, p = 0.35, g = 0.20; 95% CI − 0.23 to 0.63), CODS (3 studies, p = 0.52, g = 0.17; 95% CI − 0.35 to 0.68), CMJ (6 studies, p = 0.09, g = 0.31; 95% CI − 0.05 to 0.67), squat jump performance (5 studies, p = 0.08, g = 0.34; 95% CI − 0.04 to 0.73) and strength (4 studies, p = 0.20, g = 0.69; 95% CI − 0.37 to 1.75).

Conclusion

Overall, these findings support the notion that if the training goal is to improve strength, power and speed, supplementary weightlifting training may be advantageous for athletic development. Whilst WLT and PLYO may result in similar improvements, WLT can elicit additional benefits above that of TRT, resulting in greater improvements in weightlifting and jumping performance.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40279-021-01627-2.

Muscle Activity During Immersive Virtual Reality Exergaming Incorporating an Adaptive Cable Resistance System

The purpose of this exploratory study was to characterize muscle activation via surface electromyography (sEMG), user-perceived exertion, and enjoyment during a 30-minute session of immersive virtual reality (IVR) cable resistance exergaming. Ten healthy, college-aged males completed a signature 30-minute exergaming session using an IVR adaptive cable resistance system that incorporated six traditional compound exercises. Muscle activation (sEMG) was captured during the session with a wearable sEMG system. Rated of Perceived Exertion (RPE) and Physical Activity Enjoyment Scale (PACES) were recorded following the session. Pectoralis major showed the highest activation during chest press, deltoids showed the highest activation on overhead press, latissimus dorsi showed the highest activation during lat pulldown and row exercises, hamstrings were the most activated muscles during Romanian deadlift, and glutes showed the highest activity during squats. RPE and PACES mean scores were 14 (1) and 4.27 (0.38), respectively. IVR exergaming with resistance cable training provides an enjoyable experience and distracts practitioners from exertion while exercising at a high intensity. Results from this study suggest similar muscle activation responses compared to traditional resistance exercises as demonstrated with prior evidence. This novel form of exercise might have important repercussions for improving health outcomes among those who find it challenging to adhere to and enjoy exercise routines, as well as with little knowledge on how to progress in their resistance training. Further investigations are needed to explore long-term adaptations and to assess if IVR exergaming has additional benefits compared to traditional resistance training.

Neck Disability Index Is Better in Classification of Recovery after Whiplash Injury in Comparison with Ultrasound Shear Wave Elastography of Trapezius Muscle

A prospective observational study comparing shear wave elastography (SWE) of trapezius muscle with Neck Disability Index (NDI) in a prediction model of health status six months after a whiplash injury. Both SWE values, measured by two radiologists, and NDI scores were obtained at baseline and after physical therapy (PT) (6-month period). Those values were compared with a 3-point Likert scale (no, partial or full recovery). Twenty-two subjects completed the study. A decrease in trapezius stiffness was detected by both radiologists, statistically significant for one (Δ10.1 kPa; p = 0.04) but not for the second radiologist (Δ8.63 kPa; p = 0.07). The measurements showed excellent intra-observer (ICC 0.75–0.94) and inter-observer (ICC 0.78–0.88) reliability. After six months, fully recovered patients showed lower NDI scores than partially recovered patients (Δ22.98; p < 0.001). SWE values did not differ with the recovery status (55.6 ± 9.7 vs. 57 ± 15.8, Δ1.45; p = 0.82). The single most accurate variable in classifying health status six months after whiplash injury was the relative change of NDI, and it showed the highest accuracy (73.9%) and low Akaike information criterion (AIC = 39.2). Overall, the most accurate classification was obtained when combining NDI and SWE after physical therapy with an accuracy of 77.3% and a decrease in AIC (32.8).

A Novel Approach to Training Monotony and Acute-Chronic Workload Index: A Comparative Study in Soccer

Load is a multifactorial construct, but usually reduced to parameters of volume and intensity. In the last decades, other constructs have been proposed for assessing load, but also relying on relationships between volume and intensity. For example, Foster's Training Monotony has been used in athletes' load management simply by computing mean weekly load divided by its standard deviation, often multiplied by session rate of perceived exertion. Meanwhile, the Acute to Chronic Workload Ratio (ACWR) has been debated by the sport scientists as a useful monitoring metric and related to so-called injury prevention. None of these models includes parameters that are representative of training specificity, namely load orientation. The aim of this study is to present broader conceptual approaches translated by new indices for assessing Intraweek Training Monotony (ITM) and Acute to Chronic Workload Index (ACWI) while incorporating load orientation, session duration and weekly density (frequency normalized) in addition to parameters related to proxies of external and/or internal load. Our ITM and Foster's Training Monotony were similar in terms of average values, but very different for individualized analysis, illustrating how average values may be deceiving. While Foster's model provided clusters of values, ITM provided more scattered, individualized data. ACWI and ACWR provided very distinct qualitative information, and the two models were uncorrelated. Therefore, the models incorporating training load orientation presented in this study provide distinct and not redundant information when compared to previous models. More importantly, ITM and ACWI are metrics that are compatible to each other and might fit to coaches' monitoring targets in the short and medium terms, respectively. Because our models include several parameters, including load orientation, we contend that might provide a more complete monitoring tool. However, we suggest they are used for intraindividual comparisons and not so strongly for interindividual comparisons.

Fast-Velocity Eccentric Cycling Exercise Causes Greater Muscle Damage Than Slow Eccentric Cycling

This study aims to investigate muscle damage occurring in the early and recovery phases after fast-velocity and slow-velocity eccentric cycling. Eleven untrained men (age, 20.0 ± 1.7 years; height, 171.3 ± 6.8 cm; weight, 61.8 ± 7.7 kg; and %body fat, 13.2 ± 2.9%) performed slow-velocity maximal isokinetic eccentric cycling (slow-velocity; 30°/s) with one leg and fast-velocity (fast-velocity; 210°/s) isokinetic eccentric cycling with the other leg. Changes in maximal voluntary isokinetic concentric contraction (MVCC) torque at velocities of 30 and 210°/s, range of motion (ROM), and muscle soreness were assessed by pressure using a digital muscle stiffness instrument; thigh circumference, muscle echo intensity, and muscle stiffness were assessed before exercise, and immediately after exercise, 1 day, and 4 days after exercise. Comparing with the results obtained for slow-velocity cycling (post: 215.9 ± 32.3 Nm, day 1: 192.9 ± 47.4 Nm, day 4: 184.3 ± 47.2 Nm) and before exercise, MVCC after fast-velocity cycling significantly decreased at immediately (160.4 ± 43.5 Nm), 1 day (143.6 ± 54.1 Nm), and 4 days (150.1 ± 44.5 Nm) after exercise (p < 0.05). Significant increase in muscle soreness for vastus lateralis was observed after fast-velocity cycling (41.2 ± 16.9 mm) compared with slow-velocity cycling (23.7 ± 12.2 mm) 4 days after exercise (p < 0.05). However, no significant difference in muscle soreness was observed for rectus femoris and vastus medialis at any time points after exercise. In addition, no significant differences were observed in the ROM, thigh circumference, muscle echo intensity, and muscle stiffness. In conclusion, fast-velocity eccentric cycling causes a decrease in muscle strength and an increase in soreness as compared to slow-velocity eccentric cycling.

Effectiveness of a combined New Zealand green-lipped mussel and Antarctic krill oil supplement on markers of exercise-induced muscle damage and inflammation in untrained men

Green-lipped mussel oil (PCSO-524^®) has been shown to attenuate signs and symptoms of exercise-induced muscle damage (EIMD), and krill oil has been shown to have a protective effect against cytokine-induced tissue degradation. The purpose of this study was to compare the effects of PCSO-524^® and ESPO-572^® (75% PCSO-524^® and 25% krill oil) on signs and symptoms of EIMD. Fifty-one untrained men consumed 600 mg/d of PCSO-524^® (n = 24) or ESPO-572^® (n = 27) for 26 d prior to and 72 h following a downhill running bout. Delayed onset muscle soreness (DOMS), pressure pain threshold, limb swelling, range of motion (ROM), isometric torque, and blood markers of inflammation and muscle damage were assessed at baseline, 24, 48 and 72 h post-eccentric exercise. ESPO-572^® was 'at least as good as' PCSO-524^® and both blends were superior (p < 0.05) to placebo in lessening the increase in DOMS at 24, 48, 72 h. ESPO-572^® and PCSO-524^® were protective against joint ROM loss compared to placebo (p < 0.05) at 48 and 72 h. Notably, at 24 and 48 h, joint ROM was higher in the ESPO-572^® compared to the PCSO-524^® group (p < 0.05). No differences between the two blends for the other markers were found. ESPO-572^® is 'at least as good' as PCSO-524^® in reducing markers of muscle damage and soreness following eccentric exercise and was superior to PCSO-524^® in protecting against the loss in joint ROM during recovery. Our data support the use of ESPO-572^®, a combination of green-lipped mussel and krill oil, in mitigating the deleterious effects of EIMD.

Cardiorespiratory Fitness as a Correlate of Cardiovascular, Anthropometric, and Physical Risk Factors: Using the Ruffier Test as a Template

Background

Assessment of cardiorespiratory fitness (CRF) is a standard procedure in routine clinical practices. Early identification of risk factors through screening is vital in the fight against chronic diseases. Evaluation of CRF can impose cost implications in the clinical setting; thus, a simple and easy-to-use test is to be advocated. The Ruffier test is a simple test that can assess CRF, and it is necessary to find whether the test reflects the effects of compounding factors in CRF.

Objective

This study aims to determine the association between CRF (estimated VO2max) with cardiovascular, anthropometric, and physical risk factors using the Ruffier test.

Methods

A cross-sectional study with a sample of 52 male participants was conducted. Before the Ruffier test, each participant's body weight, height, waist circumference, skinfold thickness, thigh length, lower-limb length, thigh circumference, physical activity, blood pressure, smoking, diabetes, and pulmonary functions were recorded, and these factors correlated with CRF.

Results

There was a significant inverse relationship found between the estimated VO2max and age, height, body weight, body mass index, waist circumference, a sum of skinfold, fat percentage, thigh length, lower-limb length, thigh circumference, smoking, blood pressure, heart rates, and diabetes (p < 0.05). A significant positive correlation was found between the estimated VO2max with physical activity and respiratory functions (p < 0.05). In the multivariable model, body weight and resting heart rate were significantly inversely associated with the estimated VO2max(p < 0.05).

Conclusion

Using the Ruffier test, various risk factors of CRF are correlated with the estimated VO2max. This test reflects the effects of different compounding factors on CRF; therefore, it can be used in routine clinical practices to identify the risk factors early.

The impact of acute and chronic resistance exercise on muscle stiffness: a systematic review and meta-analysis

PURPOSE

Ultrasound is commonly used to measure changes in skeletal muscle morphology in response to both acute and chronic resistance exercise, but little is known on how muscle stiffness changes via ultrasound elastography, which was the purpose of this systematic review and meta-analysis.

METHODS

The online data bases of Pubmed, Scopus, and Web of Science were each searched up until February 2020 and the data were analyzed using a random effects model.

RESULTS

A total of eight studies (four acute and four chronic) met the inclusion criteria for the quantitative analysis. Following a single bout of exercise, muscle stiffness was increased within the first hour [ES: 1.52 (95% CI 0.14, 2.91); p = 0.031], but was no longer elevated when measured 2 days post-exercise [ES: 0.76 (95% CI - 0.32, 1.83); p = 0.16] or ≥ 7 days post-exercise [ES: 0.20 (95% CI - 0.53, 0.94); p = 0.58]. There was no impact of long-term resistance training on changes in muscle stiffness [ES: - 0.04 (95% CI - 0.24, 0.15); p = 0.653].

CONCLUSION

The primary findings from this meta-analysis indicate that muscle stiffness increases acutely following a single bout of resistance exercise, but does not change long-term with chronic resistance training when measured via ultrasound shear elastography. Given the small number of studies included in this review, future studies may wish to examine changes in muscle stiffness in response to both acute and chronic resistance exercise.

Impact of low-volume concurrent strength training distribution on muscular adaptation

OBJECTIVES

Military-, rescue- and law-enforcement personnel require a high physical capacity including muscular strength. The present study hypothesized that 9 weeks of volume matched concurrent short frequent training sessions increases strength more efficiently than less frequent longer training sessions.

DESIGN

A randomized training intervention study with functional and physiological tests before and after the intervention.

METHODS

Military conscripts (n=290) were assigned to micro-training (four 15-min strength and four 15-min endurance bouts weekly); classical-training (one 60-min strength and one 60-min endurance training session weekly) or a control-group (two 60-min standard military physical training sessions weekly).

RESULTS

There were no group difference between micro-training and classical-training in measures of strength. Standing long jump remained similar while shotput performance was reduced (P≤0.001) in all three groups. Pull-up performance increased (P≤0.001) in micro-training (7.4±4.6 vs. 8.5±4.0 repetitions, n=59) and classical-training (5.7±4.1 vs. 7.1±4.2 repetitions, n=50). Knee extensor MVC increased (P≤0.01) in all groups (micro-training, n=30, 11.5±8.9%; classical-training, n=24, 8.3±11.5% and control, n=19, 7.5±11.8%) while elbow flexor and hand grip MVC remained similar. Micro-training increased (P≤0.05) type IIa percentage from 32.5±11.0% to 37.6±12.3% (n=20) and control-group increased (P≤0.01) type IIax from 4.4±3.0% to 11.6±7.9% (n=8). In control-group type I, fiber size increased (P≤0.05) from 5121±959μm to 6481±2084μm (n=5). Satellite cell content remained similar in all groups.

CONCLUSIONS

Weekly distribution of low-volume concurrent training completed as either eight 15-min bouts or two 60-min sessions of which 50% was strength training did not impact strength gains in a real-world setting.

Physiological, anthropometric parameters, and balance skill response of healthy bankers to fitness training

Sedentary lifestyle as a predisposing factor of chronic diseases like hypertension, diabetes, stroke and obesity is a common phenomenon in the banking job. Studies suggest that fitness training improves health of bankers but has not been established among Ghanaian bankers. This study examined the physiological, anthropometric parameters, and balance skill responses of relatively healthy bankers to fitness training. Twelve bankers aged 28 to 55 years (36.41±7.16 years) in Kumasi completed a 6-month fitness training program (FTP) of 30-min gym workouts and 1-hr swimming per session. Physiological, anthropometric parameters, and balance skill variables assessments were conducted in three trials: pretraining, midtraining and post-FTP. FTP caused significant decrease in pre-post systolic blood pressure (P=0.001), diastolic blood pressure (P=0.000), heart rate (P=0.006), waist circumference (P= 0.007), waist-to-hip ratio (P=0.007), and bone density (P=0.038). There was significance decrease in body mass index (P=0.047) between pre- and midtraining status. Weight significantly decreased among the three trials (P=0.017). Pre-post opened (P=0.043) and closed (P=0.015) eye balance skills increased significantly. Effects of FTP were significantly higher in female (P<0.05). Participants who were at the stage 1 and 2 hypertensions pretraining became normotensive posttraining. Six months FTP has beneficial effects on the physiological, anthropometric parameters, and balance skill of relatively healthy bankers.

How many times per week should a muscle be trained to maximize muscle hypertrophy? A systematic review and meta-analysis of studies examining the effects of resistance training frequency

Training frequency is considered an important variable in the hypertrophic response to regimented resistance exercise. The purpose of this paper was to conduct a systematic review and meta-analysis of experimental studies designed to investigate the effects of weekly training frequency on hypertrophic adaptations. Following a systematic search of PubMed/MEDLINE, Scoups, and SPORTDiscus databases, a total of 25 studies were deemed to meet inclusion criteria. Results showed no significant difference between higher and lower frequency on a volume-equated basis. Moreover, no significant differences were seen between frequencies of training across all categories when taking into account direct measures of growth, in those considered resistance-trained, and when segmenting into training for the upper body and lower body. Meta-regression analysis of non-volume-equated studies showed a significant effect favoring higher frequencies, although the overall difference in magnitude of effect between frequencies of 1 and 3+ days per week was modest. In conclusion, there is strong evidence that resistance training frequency does not significantly or meaningfully impact muscle hypertrophy when volume is equated. Thus, for a given training volume, individuals can choose a weekly frequency per muscle groups based on personal preference.

Effects of eccentric training with different training frequencies on blood circulation, collagen fiber orientation, and mechanical properties of human Achilles tendons in vivo

PURPOSE

The purpose of the present study was to compare the effects of eccentric training with different training frequencies on the blood circulation, collagen orientation, and mechanical properties of the human Achilles tendon in vivo.

METHODS

Ten healthy males completed 12 weeks of a unilateral eccentric training program {(15 repetitions with knee straight and 15 repetitions with knee slightly bent) × 6 sets in a single session} for the plantar flexor muscles. They performed training three times per week on one side (3TW) and six times per week on the other side (6TW). Before and after training, changes in blood volume, coefficient of variation (CV) of echogenicity (reflects collagen fiber orientation), and stiffness of the Achilles tendon were compared by two-way analysis of variance.

RESULTS

The tendon blood volume tended to increase after 3TW and 6TW (p = 0.064). Tendon stiffness did not change after 3TW and 6TW, whereas the elongation of tendon structures at three force levels (50, 100, and 150 N) significantly decreased with 3TW, but not 6TW. The CV of echogenicity significantly decreased after 3TW and 6TW. However, no significant differences were observed in the relative changes in these measured variables between 3TW and 6TW.

CONCLUSION

The present results demonstrated an increase in blood volume, the alignment of collagen fibers, and unchanged stiffness of the Achilles tendon after 12 weeks of eccentric training. Furthermore, the training frequency did not influence these training-induced changes in the tendon properties.