Plyometric training as an intervention to correct altered neuromotor control during running after cycling in triathletes: A preliminary randomised controlled trial

Effects of a 4-week plyometric training on activity patterns during different phases of one-leg drop jump with focus on jump height

Athletic women have shown a higher risk of ACL injury during jump landing compared to men. Plyometric training can be an alternative way to minimize the risk of knee injuries via the changed muscle activity patterns. Hence, the aim of this study was to determine the effects of a 4-week plyometric training program on the muscle activity pattern in different phases of one-leg drop jump in active girls. Active girls were randomly allocated into 2 groups (Plyometric training = 10, Control group = 10) where the plyometric training group (PTG) performed 60 min exercises, 2 sessions/1 week for 4 weeks while the control group (CG) had their daily activity. In the pre to post test, the sEMG was recorded from the Rectus Femoris (RF), Biceps Femoris (BF), Medial Gastrocnemius (GaM), and Tibialis Anterior (TA) muscles of the dominant leg during the Preparatory phase (PP), Contact Phase (CP), Flight Phase (FP) of one-leg drop jump. Electromyography variables (Signal amplitude, Maximum activity, Time to peak (TTP), Onset and activity time and Order muscle activity) and Ergo jump variables (Time of preparatory phase (TPP), Time of contact phase (TCP), Time of flight (jump height) phase (TFP), and Explosive power were analyzed. The Univariate ANCOVA test showed a significant difference between the two groups in Activity Time, whilst adjusting for pre-test as a Covariate, only in TA muscle (F_(1,17) = 5.09, p = 0.038, η² = 0.230). In PTG. TA (- 15%), GaM (- 19%), and BF muscles (- 9%) started their activity earlier while there was no significant difference between the two groups at the Onset time. TTP of RF was significantly different between the 2 groups only in the PR phase (0.216 ± 0.07 vs 0.153 ± 0.09 s) (p = 0.049, 95% CI = 0.001, 0.127). Results of the present study suggest that a 4-week plyometric training can improve the stability of leg joints via earlier recruitment of muscles and change activity patterns in lower limb muscles. It also recommends that the preparatory phase before landing be considered an important stage in preventing sports injuries in a training program.

Heavy Resistance Training Versus Plyometric Training for Improving Running Economy and Running Time Trial Performance: A Systematic Review and Meta-analysis

BACKGROUND

As an adjunct to running training, heavy resistance and plyometric training have recently drawn attention as potential training modalities that improve running economy and running time trial performance. However, the comparative effectiveness is unknown. The present systematic review and meta-analysis aimed to determine if there are different effects of heavy resistance training versus plyometric training as an adjunct to running training on running economy and running time trial performance in long-distance runners.

METHODS

Electronic databases of PubMed, Web of Science, and SPORTDiscus were searched. Twenty-two studies completely satisfied the selection criteria. Data on running economy and running time trial performance were extracted for the meta-analysis. Subgroup analyses were performed with selected potential moderators.

RESULTS

The pooled effect size for running economy in heavy resistance training was greater (g = - 0.32 [95% confidence intervals [CIs] - 0.55 to - 0.10]: effect size = small) than that in plyometric training (g = -0.13 [95% CIs - 0.47 to 0.21]: trivial). The effect on running time trial performance was also larger in heavy resistance training (g = - 0.24 [95% CIs - 1.04 to - 0.55]: small) than that in plyometric training (g = - 0.17 [95% CIs - 0.27 to - 0.06]: trivial). Heavy resistance training with nearly maximal loads (≥ 90% of 1 repetition maximum [1RM], g = - 0.31 [95% CIs - 0.61 to - 0.02]: small) provided greater effects than those with lower loads (< 90% 1RM, g = - 0.17 [95% CIs - 1.05 to 0.70]: trivial). Greater effects were evident when training was performed for a longer period in both heavy resistance (10-14 weeks, g = - 0.45 [95% CIs - 0.83 to - 0.08]: small vs. 6-8 weeks, g = - 0.21 [95% CIs - 0.56 to 0.15]: small) and plyometric training (8-10 weeks, g = 0.26 [95% CIs - 0.67 to 0.15]: small vs. 4-6 weeks, g = - 0.06 [95% CIs 0.67 to 0.55]: trivial).

CONCLUSIONS

Heavy resistance training, especially with nearly maximal loads, may be superior to plyometric training in improving running economy and running time trial performance. In addition, running economy appears to be improved better when training is performed for a longer period in both heavy resistance and plyometric training.

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 ).

Biomechanical and physiological implications to running after cycling and strategies to improve cycling to running transition: A systematic review

OBJECTIVES

This systematic review summarises biomechanical, physiological and performance factors affecting running after cycling and explores potential effective strategies to improve performance during running after cycling.

DESIGN

Systematic review.

METHODS

The literature search included all documents available until 14th December 2021 from Medline, CINAHL, SportDiscus, and Scopus. Studies were screened against the Appraisal tool for Cross-sectional Studies to assess methodological quality and risk of bias. After screening the initial 7495 articles identified, fulltext screening was performed on 65 studies, with 39 of these included in the systematic review.

RESULTS

The majority of studies observed detrimental effects, in terms of performance, when running after cycling compared to a control run. Unclear implications were identified from a biomechanical and physiological perspective with studies presenting conflicting evidence due to varied experimental designs. Changes in cycling intensity and cadence have been tested but conflicting evidence was observed in terms of biomechanical, physiological and performance outcomes.

CONCLUSIONS

Because methods to simulate cycle to run transition varied between studies, findings were conflicting as to whether running after cycling differed compared to a form of control run. Although most studies presented were rated high to very high quality, it is not possible to state that prior cycling does affect subsequent running, from a physiological point of view, with unclear responses in terms of biomechanical outcomes. In terms of strategies to improve running after cycling, it is unclear if manipulating pedalling cadence or intensity affects subsequent running performance.

Comparison of Joint Kinematics in Transition Running and Isolated Running in Elite Triathletes in Overground Conditions

Triathletes often experience incoordination at the start of a transition run (TR); this is possibly reflected by altered joint kinematics. In this study, the first 20 steps of a run after a warm-up run (WR) and TR (following a 90 min cycling session) of 16 elite, male, long-distance triathletes (31.3 ± 5.4 years old) were compared. Measurements were executed on the competition course of the Ironman Frankfurt in Germany. Pacing and slipstream were provided by a cyclist in front of the runner. Kinematic data of the trunk and leg joints, step length, and step rate were obtained using the MVN Link inertial motion capture system by Xsens. Statistical parametric mapping was used to compare the active leg (AL) and passive leg (PL) phases of the WR and TR. In the TR, more spinal extension (~0.5–1°; p = 0.001) and rotation (~0.2–0.5°; p = 0.001–0.004), increases in hip flexion (~3°; ~65% AL−~55% PL; p = 0.001–0.004), internal hip rotation (~2.5°; AL + ~0–30% PL; p = 0.001–0.024), more knee adduction (~1°; ~80–95% AL; p = 0.001), and complex altered knee flexion patterns (~2–4°; AL + PL; p = 0.001–0.01) occurred. Complex kinematic differences between a WR and a TR were detected. This contributes to a better understanding of the incoordination in transition running.

Effects of Plyometric Jump Training on Electromyographic Activity and Its Relationship to Strength and Jump Performance in Healthy Trained and Untrained Populations: A Systematic Review of Randomized Controlled Trials

ABSTRACT

Ramirez-Campillo, R, Garcia-Pinillos, F, Chaabene, H, Moran, J, Behm, DG, and Granacher, U. Effects of plyometric jump training on electromyographic activity and its relationship to strength and jump performance in healthy trained and untrained populations: a systematic review of randomized controlled trials. J Strength Cond Res 35(7): 2053-2065, 2021-This systematic review analyzed the effects of plyometric jump training (PJT) on muscle activation assessed with surface electromyography during the performance of strength and jumping tasks in healthy populations across the lifespan. A systematic literature search was conducted in the electronic databases PubMed/MEDLINE, Web of Science, and SCOPUS. Only randomized controlled studies were eligible to be included in this study. Our search identified 17 studies comprising 23 experimental groups and 266 subjects aged 13-73 years, which were eligible for inclusion. The included studies achieved a median Physiotherapy Evidence Database score of 6. No injuries were reported among the included studies. Significant PJT-related improvements were reported in 7 of 10 studies and in 6 of 10 studies for measures of muscle activation during the performance of strength and jumping tasks, respectively. Moreover, a secondary correlational analysis showed significant positive relationships (r = 0.86; p = 0.012; r2 = 0.74) between changes in muscle activation and changes in jump performance. However, from the total number (n = 287) of muscle activation response variables analyzed for strength and jumping tasks, ∼80% (n = 226) were reported as nonsignificant when compared with a control condition. In conclusion, PJT may improve muscle activation during the performance of strength and jumping tasks. However, conflicting results were observed probably arising from (a) studies that incorporated a large number of outcomes with reduced sensitivity to PJT, (b) methodological limitations associated to muscle activation measurement during strength and jumping tasks, and (c) limitations associated with PJT prescription. Future studies in this field should strive to solve these methodological shortcomings.

Effects of jump training on physical fitness and athletic performance in endurance runners: A meta-analysis

This systematic review and meta-analysis aimed to assess the effects of jump training (JT) on measures of physical fitness and athletic performances in endurance runners. Controlled studies which involved healthy endurance runners, of any age and sex, were considered. A random-effects model was used to calculate effect sizes (ES; Hedge's g). Means and standard deviations of outcomes were converted to ES with alongside 95% confidence intervals (95%CI). Twenty-one moderate-to-high quality studies were included in the meta-analysis, and these included 511 participants. The main analyses revealed a significant moderate improvement in time-trial performance (i.e. distances between 2.0 and 5.0 km; ES = 0.88), without enhancements in maximal oxygen consumption (VO₂max), velocity at VO₂max, velocity at submaximal lactate levels, heart rate at submaximal velocities, stride rate at submaximal velocities, stiffness, total body mass or maximal strength performance. However, significant small-to-moderate improvements were noted for jump performance, rate of force development, sprint performance, reactive strength, and running economy (ES = 0.36-0.73; p < 0.001 to 0.031; I² = 0.0% to 49.3%). JT is effective in improving physical fitness and athletic performance in endurance runners. Improvements in time-trial performance after JT may be mediated through improvements in force generating capabilities and running economy.

Strength Training Improves Exercise Economy in Triathletes During a Simulated Triathlon

PURPOSE

The completion of concurrent strength and endurance training can improve exercise economy in cyclists and runners; however, the efficacy of strength training (ST) implementation to improve economy in long-distance (LD) triathletes has not yet been investigated. The purpose of this study was to investigate physiological outcomes in LD triathletes when ST was completed concurrently to endurance training.

METHODS

A total of 25 LD triathletes were randomly assigned to either 26 weeks of concurrent endurance and ST (n = 14) or endurance training only (n = 11). The ST program progressed from moderate (8-12 repetitions, ≤75% of 1-repetition maximum, weeks 0-12) to heavy loads (1-6 repetitions, ≥85% of 1-repetition maximum, weeks 14-26). Physiological and performance indicators (cycling and running economy, swim time, blood lactate, and heart rate) were measured during a simulated triathlon (1500-m swim, 60-min cycle, and 20-min run) at weeks 0, 14, and 26. Maximal strength and anthropometric measures (skinfolds and body mass) were also collected at these points.

RESULTS

The endurance strength group significantly improved maximal strength measures at weeks 14 and 26 (P < .05), cycling economy from weeks 0 to 14 (P < .05), and running economy from weeks 14 to 26 (P < .05) with no change in body mass (P > .05). The endurance-only group did not significantly improve any economy measures.

CONCLUSIONS

The addition of progressive load ST to LD triathletes' training programs can significantly improve running and cycling economy without an increase in body mass.

Effects of Strength Training on the Physiological Determinants of Middle- and Long-Distance Running Performance: A Systematic Review

Background

Middle- and long-distance running performance is constrained by several important aerobic and anaerobic parameters. The efficacy of strength training (ST) for distance runners has received considerable attention in the literature. However, to date, the results of these studies have not been fully synthesized in a review on the topic.

Objectives

This systematic review aimed to provide a comprehensive critical commentary on the current literature that has examined the effects of ST modalities on the physiological determinants and performance of middle- and long-distance runners, and offer recommendations for best practice.

Methods

Electronic databases were searched using a variety of key words relating to ST exercise and distance running. This search was supplemented with citation tracking. To be eligible for inclusion, a study was required to meet the following criteria: participants were middle- or long-distance runners with ≥ 6 months experience, a ST intervention (heavy resistance training, explosive resistance training, or plyometric training) lasting ≥ 4 weeks was applied, a running only control group was used, data on one or more physiological variables was reported. Two independent assessors deemed that 24 studies fully met the criteria for inclusion. Methodological rigor was assessed for each study using the PEDro scale.

Results

PEDro scores revealed internal validity of 4, 5, or 6 for the studies reviewed. Running economy (RE) was measured in 20 of the studies and generally showed improvements (2–8%) compared to a control group, although this was not always the case. Time trial (TT) performance (1.5–10 km) and anaerobic speed qualities also tended to improve following ST. Other parameters [maximal oxygen uptake (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{ \hbox{max} }}}$$\end{document}V˙O2max), velocity at \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\dot{V}{\text{O}}_{{2{ \hbox{max} }}}$$\end{document}V˙O2max, blood lactate, body composition] were typically unaffected by ST.

Conclusion

Whilst there was good evidence that ST improves RE, TT, and sprint performance, this was not a consistent finding across all works that were reviewed. Several important methodological differences and limitations are highlighted, which may explain the discrepancies in findings and should be considered in future investigations in this area. Importantly for the distance runner, measures relating to body composition are not negatively impacted by a ST intervention. The addition of two to three ST sessions per week, which include a variety of ST modalities are likely to provide benefits to the performance of middle- and long-distance runners.

Therapy and Rehabilitation for Upper Extremity Injuries in Athletes

The approach to rehabilitation of upper extremity injuries in athletes differs from traditional rehabilitation protocols. In general, athletes have higher functional demands and wish to return to competitive sport in a timely manner. Comprehensive rehabilitation must therefore be balanced with a timely and safe return to sport. Several rehabilitation programs and adjunctive therapies are available to hasten convalescence while minimizing the athlete's risks of reinjury. Here, we review techniques for soft tissue mobilization and strength training in athletic populations. We also discuss orthotics, taping, and alternative therapies used in rehabilitation and evaluate the evidence in support of these modalities.

Muscle performance following an acute bout of plyometric training combined with low or high intensity weight exercise

To determine the time course of performance responses after an acute bout of plyometric exercise combined with high and low intensity weight training, a 3-group (including a control group), repeated-measures design was employed. Changes in performance were monitored through jumping ability by measuring countermovement and squat jumping, and strength performance assessment through isometric and isokinetic testing of knee extensors (at two different velocities). Participants in both experimental groups performed a plyometric protocol consisting of 50 jumps over 50 cm hurdles and 50 drop jumps from a 50 cm plyometric box. Additionally, each group performed two basic weight exercises consisting of leg presses and leg extensions at 90-95% of maximum muscle strength for the high intensity group and 60% of maximum muscle strength for the low intensity group. The results of the study suggest that an acute bout of intense plyometric exercise combined with weight exercise induces time-dependent changes in performance, which are also dependent on the nature of exercise protocol and testing procedures. In conclusion, acute plyometric exercise with weight exercise may induce a substantial decline in jumping performance for as long as 72 hours but not in other forms of muscle strength.

Longitudinal changes in response to a cycle-run field test of young male national "talent identification" and senior elite triathlon squads

This study investigated the changes in cardiorespiratory response and running performance of 9 male "Talent Identification" (TID) and 6 male Senior Elite (SE) Spanish National Squad triathletes during a specific cycle-run (C-R) test. The TID and SE triathletes (initial age 15.2 ± 0.7 vs. 23.8 ± 5.6 years, p = 0.03; V(O2)max 77.0 ± 5.6 vs. 77.8 ± 3.6 ml · kg(-1) · min(-1), nonsignificant) underwent 3 tests through the competitive period and the preparatory period, respectively, of 2 consecutive seasons: test 1 was an incremental cycle test to determine the ventilatory threshold (Th(vent)); test 2 (C-R) was 30-minute constant load cycling at the Th(vent) power output followed by a 3-km time-trial run; and test 3 (isolated control run [R]) was an isolated 3-km time-trial control run, in randomized counterbalanced order. In both seasons, the time required to complete the C-R 3-km run was greater than for R in TID (11:09 ± 00:24 vs. 10:45 ± 00:16 min:ss, p < 0.01 and 10:24 ± 00:22 vs. 10:04 ± 00:14, p = 0.006, for season 2005-2006 and 2006-2007, respectively) and SE (10:15 ± 00:19 vs. 09:45 ± 00:30, p < 0.001 and 09:51 ± 00:26 vs. 09:46 ± 00:06, p = 0.02 for season 2005-2006 and 2006-2007, respectively). Compared with the first season, the completion of the time-trial run was faster in the second season (6.6%, p < 0.01 and 6.4%, p < 0.01, for C-R and R tests, respectively) only in TID. Changes in post cycling run performance were accompanied by changes in pacing strategy, but there were only slight or nonsignificant changes in the cardiorespiratory response. Thus, the negative effect of cycling on performance may persist, independently of the period, over 2 consecutive seasons in TID and SE triathletes; however, improvements over time suggests that monitoring running pacing strategy after cycling may be a useful tool to control performance and training adaptations in TID.