In-Season Strength Training in Elite Junior Swimmers: The Role of the Low-Volume, High-Velocity Training on Swimming Performance

Effects of light- vs. heavy-load squat training on velocity, strength, power, and total mechanical work in recreationally trained men and women

The purpose of this study was to investigate the effects of light and heavy loads in the squat exercise on kinematics and mechanical variables in recreationally trained men and women. Twenty-two men and sixteen women were assigned to 4 groups: 40% and 80% one-repetition maximum (1RM) male (M40 and M80) and female (F40 and F80). Over 6 weeks, participants performed twice a week the full back-squat (SQ) exercise with initially equated relative volume load (Sets*Repetitions/Set*%1RM). All groups performed different amounts of work (p < 0.05), while relative work (work/1RM) only differed between load groups (p < 0.001). There was no significant Time*Sex*Load interaction. Based on the magnitude of effect sizes: M80 achieved small improvements in the SQ maximum isometric force (MIF; ES = 0.43, 95% CI [0.16, 0.81]); small gains in squat estimated 1RM strength were observed in the 80%-1RM groups (M80: 0.42 [0.18, 0.77]; F80: 0.44 [0.26, 0.76]) and the F40 group (0.42 [0.17, 0.81]); all groups made moderate to large gains in the average velocity attained against heavy loads (> 60%1RM; F40: 1.20 [0.52, 2.27]; F80: 2.20 [1.23, 3.93]; M40: 0.85 [0.29, 1.59]; M80: 1.03 [0.55, 1.77]), as well as small to moderate improvements in the average velocity against light loads (< 60%1RM; F40: 0.49[-0.24, 1.68]; F80: 1.10 [0.06, 3.16]; M40: 0.80 [0.41, 1.35]; M80: 0.93 [0.25, 1.84]). Lastly, only the F40 group showed small improvements in countermovement jump (CMJ) height (ES = 0.65 [0.14, 1.37]). In conclusion, light and heavy loads produced similar strength gains in men and women when initially equated by relative volume load, although the standardized mean differences suggest nuances depending on the sample and task.

The Effects of Resistance Training on Muscular Fitness, Muscle Morphology, and Body Composition in Elite Female Athletes: A Systematic Review

BACKGROUND

Well programmed strength and conditioning training is an indispensable part of the long-term training process for athletes in individual and team sports to improve performance and prevent injuries. Yet, there is a limited number of studies available that examine the effects of resistance training (RT) on muscular fitness and physiological adaptations in elite female athletes.

OBJECTIVES

This systematic review aimed to summarize recent evidence on the long-term effects of RT or combinations of RT with other strength-dominated exercise types on muscular fitness, muscle morphology, and body composition in female elite athletes.

MATERIALS AND METHODS

A systematic literature search was conducted in nine electronic databases (Academic Search Elite, CINAHL, ERIC, Open Access Theses and Dissertations, Open Dissertations, PsycINFO, PubMed/MEDLINE, Scopus, and SPORTDiscus) from inception until March 2022. Key search terms from the MeSH database such as RT and strength training were included and combined using the operators "AND," "OR," and "NOT". The search syntax initially identified 181 records. After screening for titles, abstracts, and full texts, 33 studies remained that examined the long-term effects of RT or combinations of RT with other strength-dominated exercise types on muscular fitness, muscle morphology, and body composition in female elite athletes.

RESULTS

Twenty-four studies used single-mode RT or plyometric training and nine studies investigated the effects of combined training programs such as resistance with plyometric or agility training, resistance and speed training, and resistance and power training. The training duration lasted at least 4 weeks, but most studies used ~ 12 weeks. Studies were generally classified as 'high-quality' with a mean PEDro score of 6.8 (median 7). Irrespective of the type or combination of RT with other strength-dominated exercise regimens (type of exercise, exercise duration, or intensity), 24 out of 33 studies reported increases in muscle power (e.g., maximal and mean power; effect size [ES]: 0.23 < Cohen's d < 1.83, small to large), strength (e.g., one-repetition-maximum [1RM]; ES: 0.15 < d < 6.80, small to very large), speed (e.g., sprint times; ES: 0.01 < d < 1.26, small to large), and jump performance (e.g., countermovement/squat jump; ES: 0.02 < d < 1.04, small to large). The nine studies that examined the effects of combined training showed significant increases on maximal strength (ES: 0.08 < d < 2.41, small to very large), muscle power (ES: 0.08 < d < 2.41, small to very large), jump and sprint performance (ES: 0.08 < d < 2.41, small to very large). Four out of six studies observed no changes in body mass or percentage of body fat after resistance or plyometric training or combined training (ES: 0.026 < d < 0.492, small to medium). Five out of six studies observed significant changes in muscle morphology (e.g., muscle thickness, muscle fiber cross-sectional area; ES: 0.23 < d < 3.21, small to very large). However, one study did not find any changes in muscle morphology (i.e., muscle thickness, pennation angle; ES: 0.1 < d < 0.19, small).

CONCLUSION

Findings from this systematic review suggest that RT or combined RT with other strength-dominated exercise types leads to significant increases in measures of muscle power, strength, speed, and jump performance in elite female athletes. However, the optimal dosage of programming parameters such as training intensity and duration necessary to induce large effects in measures of muscular fitness and their physiological adaptations remain to be resolved in female elite athletes.

IMPROVEMENT OF PHYSICAL CONDITIONS IN TENNIS PLAYERS UNDER HIGH ALTITUDES

ABSTRACT Introduction: Due to the lower atmospheric density at high altitudes, the spherical surface of the table tennis ball offers less resistance, requiring higher performance from its players. The athletes' reaction time and movement speed can improve significantly. Objective: This paper studies the changes in the fitness level of Chinese table tennis players under training at high altitudes. These results can serve as a reference to formulate and implement the training strategy of the Chinese table tennis team. Methods: The performance of 12 outstanding table tennis players in the competition was explored. After arriving at the high altitude, the athletes practiced training for four weeks. The athletes' biochemical parameters and heart rates were evaluated before and after training. These data were statistically treated. Results: The heart rate of the athletes in the third week after the experiment was lower than before, with no significant difference (P>0.05). The hematocrit value of table tennis players in training showed a temporary elevation after one week, significantly different from that before the experiment (P<0.05). After two weeks of exercise at a high altitude, the hematocrit value of the athletes remained at a high level (P<0.05). Conclusion: Table tennis players can improve their physical conditions with training at high altitudes, including aerobic and anaerobic properties. High-intensity exercise at high altitudes is also beneficial for improving athletes' strength, speed, and reaction time quality. Level of evidence II; Therapeutic studies - investigating treatment outcomes.

CHANGES IN VO2MAX CAUSED BY AEROBIC EXERCISE IN SWIMMERS

ABSTRACT Introduction The maximal oxygen consumption rate (VO2max) can directly reflect the body's aerobic metabolism and oxygen delivery system. This is a measure of aerobic capacity used to monitor swimmers’ levels and their strength and speed performance. Objective Verify the changes in VO2max when incorporating aerobic exercise training into swimmers’ regular training. Methods 12 volunteer swimmers were divided into two categories: strength training group and regular training group. Both groups performed a fitness test on the 200-meter track before starting the training. VO2 maximal was measured and worked out statistically to verify the results of this competition. The effects of aerobic exercise on the strength and competitive status of the athletes were investigated according to an updated literature review. Results There was a significant change in the maximal oxygen uptake of the athletes after the experimental protocol. The athletes in the strength training group increased their VO2 max compared to the regular training group. The results showed a significant difference in the VO2max index before and after strength training (P<0.05). This suggests that strength training has a significant effect on maximal oxygen consumption. Conclusion Strength training interventions significantly affect athletes’ maximal oxygen consumption intensity and exercise capacity. The aerobic exercise intervention showed evidence of improving the competitive level of athletes. Level of evidence II; Therapeutic studies -investigation of treatment outcomes.

Association between the dry-land strength & power and the kick start kinetics in elite male and female swimmers

The aim of this research was to determine the association between dry-land exercises and the start kinetics in elite swimmers. Fourteen swimmers (eight males and six females) included in a national team took part in this study. A fixed smith-machine was used to measure the maximal full squat strength (Smax). The height of squat (SJ) and countermovement (CMJ) jumps were collected with a contact mat. The ground reaction force of the kick starts in the three-dimensional axis (Fz horizontal; Fy, vertical; Fx, lateral) was obtained by an instrumented force plate in the starting block. Overall, the Smax showed a high and significant association with Fz (r = 0.60) and Fy (r = 0.87). Moderate and significant associations were found between Fy and SJ (r = 0.51) and CMJ (r = 0.57). While Smax in males showed high association with Fy (r = 0.77), the Smax for females showed greater association with Fz (r = 0.84). As conclusion, the full back squat seems to be the dry-land exercise with higher association with the kick start kinetics. While in males the full squat defines better the vertical component, for females it defines the horizontal one.

Effects of Plyometric Jump Training on Measures of Physical Fitness and Sport-Specific Performance of Water Sports Athletes: A Systematic Review with Meta-analysis

Background

A growing body of literature is available regarding the effects of plyometric jump training (PJT) on measures of physical fitness (PF) and sport-specific performance (SSP) in-water sports athletes (WSA, i.e. those competing in sports that are practiced on [e.g. rowing] or in [e.g. swimming; water polo] water). Indeed, incoherent findings have been observed across individual studies making it difficult to provide the scientific community and coaches with consistent evidence. As such, a comprehensive systematic literature search should be conducted to clarify the existent evidence, identify the major gaps in the literature, and offer recommendations for future studies.

Aim

To examine the effects of PJT compared with active/specific-active controls on the PF (one-repetition maximum back squat strength, squat jump height, countermovement jump height, horizontal jump distance, body mass, fat mass, thigh girth) and SSP (in-water vertical jump, in-water agility, time trial) outcomes in WSA, through a systematic review with meta-analysis of randomized and non-randomized controlled studies.

Methods

The electronic databases PubMed, Scopus, and Web of Science were searched up to January 2022. According to the PICOS approach, the eligibility criteria were: (population) healthy WSA; (intervention) PJT interventions involving unilateral and/or bilateral jumps, and a minimal duration of ≥ 3 weeks; (comparator) active (i.e. standard sports training) or specific-active (i.e. alternative training intervention) control group(s); (outcome) at least one measure of PF (e.g. jump height) and/or SSP (e.g. time trial) before and after training; and (study design) multi-groups randomized and non-randomized controlled trials. The Physiotherapy Evidence Database (PEDro) scale was used to assess the methodological quality of the included studies. The DerSimonian and Laird random-effects model was used to compute the meta-analyses, reporting effect sizes (ES, i.e. Hedges’ g) with 95% confidence intervals (95% CIs). Statistical significance was set at p ≤ 0.05. Certainty or confidence in the body of evidence for each outcome was assessed using Grading of Recommendations Assessment, Development, and Evaluation (GRADE), considering its five dimensions: risk of bias in studies, indirectness, inconsistency, imprecision, and risk of publication bias.

Results

A total of 11,028 studies were identified with 26 considered eligible for inclusion. The median PEDro score across the included studies was 5.5 (moderate-to-high methodological quality). The included studies involved a total of 618 WSA of both sexes (330 participants in the intervention groups [31 groups] and 288 participants in the control groups [26 groups]), aged between 10 and 26 years, and from different sports disciplines such as swimming, triathlon, rowing, artistic swimming, and water polo. The duration of the training programmes in the intervention and control groups ranged from 4 to 36 weeks. The results of the meta-analysis indicated no effects of PJT compared to control conditions (including specific-active controls) for in-water vertical jump or agility (ES =  − 0.15 to 0.03; p = 0.477 to 0.899), or for body mass, fat mass, and thigh girth (ES = 0.06 to 0.15; p = 0.452 to 0.841). In terms of measures of PF, moderate-to-large effects were noted in favour of the PJT groups compared to the control groups (including specific-active control groups) for one-repetition maximum back squat strength, horizontal jump distance, squat jump height, and countermovement jump height (ES = 0.67 to 1.47; p = 0.041 to < 0.001), in addition to a small effect noted in favour of the PJT for SSP time-trial speed (ES = 0.42; p = 0.005). Certainty of evidence across the included studies varied from very low-to-moderate.

Conclusions

PJT is more effective to improve measures of PF and SSP in WSA compared to control conditions involving traditional sport-specific training as well as alternative training interventions (e.g. resistance training). It is worth noting that the present findings are derived from 26 studies of moderate-to-high methodological quality, low-to-moderate impact of heterogeneity, and very low-to-moderate certainty of evidence based on GRADE.

Trial registration The protocol for this systematic review with meta-analysis was published in the Open Science platform (OSF) on January 23, 2022, under the registration doi https://doi.org/10.17605/OSF.IO/NWHS3 (internet archive link: https://archive.org/details/osf-registrations-nwhs3-v1).

Toward a New Paradigm in Resistance Training by Means of Velocity Monitoring: A Critical and Challenging Narrative

For more than a century, many concepts and several theories and principles pertaining to the goals, organization, methodology and evaluation of the effects of resistance training (RT) have been developed and discussed between coaches and scientists. This cumulative body of knowledge and practices has contributed substantially to the evolution of RT methodology. However, a detailed and rigorous examination of the existing literature reveals many inconsistencies that, unless resolved, could seriously hinder further progress in our field. The purpose of this review is to constructively expose, analyze and discuss a set of anomalies present in the current RT methodology, including: (a) the often inappropriate and misleading terminology used, (b) the need to clarify the aims of RT, (c) the very concept of maximal strength, (d) the control and monitoring of the resistance exercise dose, (e) the existing programming models and (f) the evaluation of training effects. A thorough and unbiased examination of these deficiencies could well lead to the adoption of a revised paradigm for RT. This new paradigm must guarantee a precise knowledge of the loads being applied, the effort they involve and their effects. To the best of our knowledge, currently this can only be achieved by monitoring repetition velocity during training. The main contribution of a velocity-based RT approach is that it provides the necessary information to know the actual training loads that induce a specific effect in each athlete. The correct adoption of this revised paradigm will provide coaches and strength and conditioning professionals with accurate and objective information concerning the applied load (relative load, level of effort and training effect). This knowledge is essential to make rational and informed decisions and to improve the training methodology itself.

Effect of Resistance Training Methods and Intensity on the Adolescent Swimmer's Performance: A Systematic Review

Background

Resistance training has been widely used in various sports and improves competition performance, especially in swimming. Swimming performance is highly dependent on muscle strength, especially short distances. For adolescent athletes, the existing literature has bound to prove that resistance training is undoubtedly bound to improve swimmers' performance.

Objectives

This study adopts a systematic literature review to (1) examine the effects of resistance training on the performance of adolescent swimmers, and (2) summarize their training methods and intensity.

Methods

The literature search was undertaken in five international databases: the SCOUPS, PubMed, EBSCOhost (SPORTDiscus), CNKL, Web of Science. The searches covered documents in English and Chinese published until 30th December 2020. Electronic databases using various keywords related to "strength training" and "adolescent swimmers" were searched. Sixteen studies met the inclusion and exclusion criteria where the data was then systematically reviewed using the PRISMA guideline. Furthermore, the physical therapy evidence database (PEDro) scale was used to measure each study's scientific rigor.

Results

This review found that to improve the swimming performance of adolescents, two types of resistance training were used, specifically in water and on land, where both types of training can improve swimming performance. In addition, training with two types of resistance machines were better in the water than with one equipment. Resistance training can improve the swimming performance of adolescent swimmers at 50 m, 100 m, 200 m and 400 m distances. However, most studies only focused on the swimming performance at 50 m and 100 m lengths. A low-intensity, high-speed resistance training programme is recommended for adolescent swimmers to obtain the best training results.

Conclusion

Water or land resistance training can improve the swimming performance. Given that both types of exercises have their strengths and weaknesses, combining these methods may enhance the swimmers' performance. In addition, despite the starting and turning phases consuming up to one-third of the total swimming time for short distances, literature in this area is limited.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero, identifier: CRD42021231510.

Comparison between Dry-Land and Swimming Priming on 50 m Crawl Performance in Well-Trained Adolescent Swimmers

The purpose of the study was to investigate the effect of dry-land priming (DLP) versus swimming priming (SP) on the 50 m crawl performance of well-trained adolescent swimmers. Thirteen adolescent swimmers were randomly assigned to perform either a DLP or SP 24 h prior to a 50 m sprint crawl time-trial. Baseline measurements included a 50 m sprint crawl time-trial as a control (C) condition, the evaluation of body composition, countermovement jump (CMJ), isometric peak torque (IPT), and rate of torque development (RTD). Rating of perceived exertion (RPE) was obtained following the DLP and SP programs. Both DLP and SP significantly decreased the 50 m crawl time-trial, by −2.51 ± 2.43% and −2.59 ± 1.89% (p < 0.01), respectively, compared with the C time-trial. RPE was not different between DLP and SP (p = 0.919). CMJ performance remained unchanged after DLP and SP programs compared with the C trial (p > 0.05). The percentage decrease in the 50 m crawl after DLP was significantly correlated with the percentage decrease in the 50 m crawl following SP (r = 0.720, p = 0.006). CMJ power, lean body mass, IPT, and RTD were significantly correlated with 50 m crawl performance. These results suggest that both DLP and SP strategies, when applied 24 h prior to a 50 m crawl time-trial, may enhance performance in well-trained adolescent swimmers.