Calf Compression Sleeves Change Biomechanics but Not Performance and Physiological Responses in Trail Running

The Effects of Lower Leg Compression Garments on Lower Extremity Sports Injuries, Subjective Fatigue and Biomechanical Variables: A Systematic Review with Meta-analysis

The objective of this study was to systematically review the literature on the effect of CGs versus non-CGs (such as regular socks) or versus placebo garments on 1) the incidence of lower extremity sports injuries and 2) subjective ratings of fatigue and biomechanical variables in athletes at participating in any sport that required any level of running performance, given that fatigue-related biomechanical alterations may increase the risk of sports injuries. This study was a systematic review with meta-analyses. PubMed, Embase, CINAHL, Cochrane, PEDro, and Scopus were searched for eligible studies until 7 July 2021. Two reviewers independently assessed the risk of bias using the Cochrane Collaboration's tool for risk of bias. Meta-analyses were performed using a random-effects model. The Grades of Recommendation, Assessment, Development and Evaluation (GRADE) approach was used to assess the certainty of evidence for all outcome measures. Twenty-three studies, all with a high risk of bias, were included. Nineteen studies were used in the meta-analyses. No studies focused on the effect of CGs on the incidence of lower extremity sports injuries in athletes. Seventeen studies investigated the effect of CGs on subjective ratings of fatigue, but meta-analysis showed no difference in effectiveness between CGs versus non-CGs (such as regular socks) and versus placebo CGs (low certainty evidence). Because of heterogeneity, pooling of the results was not possible for the biomechanical variables. Nonetheless, low certainty evidence showed no effect of CGs. We identified no evidence for a beneficial or detrimental effect of lower leg CGs on the occurrence of lower extremity sports injuries, subjective ratings of fatigue, or biomechanical variables in athletes at any level of running performance. Based on the variable use of running tests, definitions used for biomechanical variables, and reporting of CG characteristics and more standardized reporting is recommended for future studies evaluating CGs.

Muscle Oximetry in Sports Science: An Updated Systematic Review

BACKGROUND

In the last 5 years since our last systematic review, a significant number of articles have been published on the technical aspects of muscle near-infrared spectroscopy (NIRS), the interpretation of the signals and the benefits of using the NIRS technique to measure the physiological status of muscles and to determine the workload of working muscles.

OBJECTIVES

Considering the consistent number of studies on the application of muscle oximetry in sports science published over the last 5 years, the objectives of this updated systematic review were to highlight the applications of muscle oximetry in the assessment of skeletal muscle oxidative performance in sports activities and to emphasize how this technology has been applied to exercise and training over the last 5 years. In addition, some recent instrumental developments will be briefly summarized.

METHODS

Preferred Reporting Items for Systematic Reviews guidelines were followed in a systematic fashion to search, appraise and synthesize existing literature on this topic. Electronic databases such as Scopus, MEDLINE/PubMed and SPORTDiscus were searched from March 2017 up to March 2023. Potential inclusions were screened against eligibility criteria relating to recreationally trained to elite athletes, with or without training programmes, who must have assessed physiological variables monitored by commercial oximeters or NIRS instrumentation.

RESULTS

Of the identified records, 191 studies regrouping 3435 participants, met the eligibility criteria. This systematic review highlighted a number of key findings in 37 domains of sport activities. Overall, NIRS information can be used as a meaningful marker of skeletal muscle oxidative capacity and can become one of the primary monitoring tools in practice in conjunction with, or in comparison with, heart rate or mechanical power indices in diverse exercise contexts and across different types of training and interventions.

CONCLUSIONS

Although the feasibility and success of the use of muscle oximetry in sports science is well documented, there is still a need for further instrumental development to overcome current instrumental limitations. Longitudinal studies are urgently needed to strengthen the benefits of using muscle oximetry in sports science.

Upper body compression wear improves muscle oxygenation following intense video game training: a randomized cross-over study among competitive gamers

BACKGROUND

Esport players require a high number of action moves per minute to play, with substantial contractions of the wrist extensor muscles. Players frequently suffer from acute fatigue. The purpose of this study was to examine the use of below the elbow compression sleeves on Sm02 during intense aim training. Secondly, to examine players' performance and perception with and without compression.

METHODS

This study was conducted at the New York Institute of Technology and enrolled fifteen collegiate esport players, 2 women and 13 men (age 21.2 ± 2.2). All subjects signed written consent. Participants performed 3 high intensity bouts of an aim trainer followed by a 15-minute rest before doing another 3 bouts of high intensity training conducting the other arm of the study. The compression wear order was randomized. The primary outcome included Sm02 of the extensor carpi radialis longus using near-infrared spectrometry. Secondary outcomes included Kills Per Second (KPS), Score, Total Time to Kill (TTK), accuracy, and perceived performance.

RESULTS

Following 15 min of recovery, there was a significant rise in Sm02 while wearing the compression sleeve compared to no compression sleeve (p = 0.004). No change in Sm02 was seen while gaming. In trials 1 and 2, wearing the compression sleeve resulted in a significant increase in KPS and score when compared to not wearing it (p = 0.002,0.006). Although TTK and accuracy did not alter, 46.7% of participants believed the compression sleeve aided their performance.

CONCLUSIONS

This study provides support that wearing below the elbow upper body compression sleeves while performing high intensity gaming may reduce fatigue, improve muscle recovery and gaming performance.

TRIAL REGISTRATION

Clinicaltrials.gov identifier NCT05037071. Registered 08/09/2021. URL: Arm Compression on Muscle Oxygen Saturation - Full Text View - ClinicalTrials.gov.

Effect of Kinesio tape and Compression sleeves on delayed onset of muscle soreness: a single-blinded randomized controlled trial

BACKGROUND

Both Kinesio Tape (KT) and Compression Sleeves (CS) can relieve Delayed Onset Muscle Soreness (DOMS) to a certain extent, but there is no study report on the difference in the effectiveness of the KT and CS whether the effect is better when used at the same time. The purpose of this study was to compare the effects of KT and CS on the recovery of muscle soreness, isokinetic strength, and body fatigue after DOMS.

METHODS

In this single-blinded randomized controlled trial, 32 participants aged 18 to 24 years were randomly divided into Control group (CG), Compression Sleeves group (CSG), Kinesio Tape group (KTG), Compression Sleeves and Kinesio Tape group (CSKTG), between October 2021 and January 2022. KTG uses Kinesio Tape, CSG wears Compression Sleeves, and CSKTG uses both Compression Sleeves and Kinesio Tape. Outcomes were performed at five-time points (baseline, 0 h, 24 h, 48 h, 72 h), Primary outcome was pain level Visual Analogue Scale (VAS), and Secondary outcomes were Interleukin 6, Peak Torque/Body Weight, Work Fatigue. Statistical analyses were performed using the repeated measures analysis of variance method.

SETTING

Laboratory.

RESULTS

After the intervention, VAS reached the highest at 24 h after exercise-induced muscle soreness, while the KTG and CSG at each time point were less than CG, and the scores of CSKTG at 24 h and 48 h were less than those of KTG and CSG in the same period (P < 0.05). Interleukin 6, at 24 h, CSKTG is lower than KTG 0.71(95%CI: 0.43 to 1.86) and CG 1.68(95%CI: 0.06 to 3.29). Peak Torque/Body Weight, at 24 h, CG was lower than CSKTG 0.99(95%CI: 0.42 to 1.56), KTG 0.94(95%CI: 0.37 to 1.52), and CSG 0.72(95%CI: 0.14 to 1.29); at 72 h, CG was lower than CSKTG 0.65(95%CI: 0.13 to 1.17) and KTG 0.58(95%CI: 0.06 to 1.10). Work Fatigue, at 24 h, CG was lower than KTG 0.10(95%CI: 0.02 to 1.78) and CSKTG 0.01(95%CI: -0.07 to 0.09). At 48 h, CG was lower than KTG 0.10(95%CI: 0.13 to 1.17) and CSKTG 0.11(95%CI: 0.03 to 0.18).

CONCLUSIONS

Kinesio Tape can significantly reduce DOMS pain, and Kinesio Tape has a better recovery effect on Delayed Onset Muscle Soreness than Compression Sleeves. Kinesio Tape combined with Compression Sleeves is helpful to alleviate the Delayed Onset Muscle Soreness pain, speeding up the recovery of muscle strength, and shortening the recovery time after Delayed Onset Muscle Soreness.

TRIAL REGISTRATION

Registration number: This study was also registered on 11/10/2021, at the Chinese Clinical Trial Registry (ChiCTR2100051973).

Do Sports Compression Garments Alter Measures of Peripheral Blood Flow? A Systematic Review with Meta-Analysis

BACKGROUND

One of the proposed mechanisms underlying the benefits of sports compression garments may be alterations in peripheral blood flow.

OBJECTIVE

We aimed to determine if sports compression garments alter measures of peripheral blood flow at rest, as well as during, immediately after and in recovery from a physiological challenge (i.e. exercise or an orthostatic challenge).

METHODS

We conducted a systematic literature search of databases including Scopus, SPORTDiscus and PubMed/MEDLINE. The criteria for inclusion of studies were: (1) original papers in English and a peer-reviewed journal; (2) assessed effect of compression garments on a measure of peripheral blood flow at rest and/or before, during or after a physiological challenge; (3) participants were healthy and without cardiovascular or metabolic disorders; and (4) a study population including athletes and physically active or healthy participants. The PEDro scale was used to assess the methodological quality of the included studies. A random-effects meta-analysis model was used. Changes in blood flow were quantified by standardised mean difference (SMD) [± 95% confidence interval (CI)].

RESULTS

Of the 899 articles identified, 22 studies were included for the meta-analysis. The results indicated sports compression garments improve overall peripheral blood flow (SMD = 0.32, 95% CI 0.13, 0.51, p = 0.001), venous blood flow (SMD = 0.37, 95% CI 0.14, 0.60, p = 0.002) and arterial blood flow (SMD = 0.30, 95% CI 0.01, 0.59, p = 0.04). At rest, sports compression garments did not improve peripheral blood flow (SMD = 0.18, 95% CI - 0.02, 0.39, p = 0.08). However, subgroup analyses revealed sports compression garments enhance venous (SMD = 0.31 95% CI 0.02, 0.60, p = 0.03), but not arterial (SMD = 0.12, 95% CI - 0.16, 0.40, p = 0.16), blood flow. During a physiological challenge, peripheral blood flow was improved (SMD = 0.44, 95% CI 0.19, 0.69, p = 0.0007), with subgroup analyses revealing sports compression garments enhance venous (SMD = 0.48, 95% CI 0.11, 0.85, p = 0.01) and arterial blood flow (SMD = 0.44, 95% CI 0.03, 0.86, p = 0.04). At immediately after a physiological challenge, there were no changes in peripheral blood flow (SMD = - 0.04, 95% CI - 0.43, 0.34, p = 0.82) or subgroup analyses of venous (SMD = - 0.41, 95% CI - 1.32, 0.47, p = 0.35) and arterial (SMD = 0.12, 95% CI - 0.26, 0.51, p = 0.53) blood flow. In recovery, sports compression garments did not improve peripheral blood flow (SMD = 0.25, 95% CI - 0.45, 0.95, p = 0.49). The subgroup analyses showed enhanced venous (SMD = 0.67, 95% CI 0.17, 1.17, p = 0.009), but not arterial blood flow (SMD = 0.02, 95% CI - 1.06, 1.09, p = 0.98).

CONCLUSIONS

Use of sports compression garments enhances venous blood flow at rest, during and in recovery from, but not immediately after, a physiological challenge. Compression-induced changes in arterial blood flow were only evident during a physiological challenge.

Compression-induced improvements in post-exercise recovery are associated with enhanced blood flow, and are not due to the placebo effect

The aim of this study was to investigate the physiological effects of compression tights on blood flow following exercise and to assess if the placebo effect is responsible for any acute performance or psychological benefits. Twenty-two resistance-trained participants completed a lower-body resistance exercise session followed by a 4 h recovery period. Participants were assigned a post-exercise recovery intervention of either compression tights applied for 4 h (COMP), placebo tablet consumed every hour for 4 h (PLA) or control (CON). Physiological (markers of venous return, muscle blood flow, blood metabolites, thigh girth), performance (countermovement jump, isometric mid-thigh pull), and psychological measures (perceived muscle soreness, total quality of recovery) were collected pre-exercise, immediately post-exercise, at 30 (markers of venous return and muscle blood flow) and 60 min (blood metabolites, thigh girth and psychological measures) intervals during 4 h of recovery, and at 4 h, 24 h and 48 h post-exercise. No significant (P > 0.05) differences were observed between interventions. However, effect size analysis revealed COMP enhanced markers of venous return, muscle blood flow, recovery of performance measures, psychological measures and reduced thigh girth compared to PLA and CON. There were no group differences in blood metabolites. These findings suggest compression tights worn after resistance exercise enhance blood flow and indices of exercise recovery, and that these benefits were not due to a placebo effect.

Putting the Squeeze on Compression Garments: Current Evidence and Recommendations for Future Research: A Systematic Scoping Review

Background

Compression garments are regularly worn during exercise to improve physical performance, mitigate fatigue responses, and enhance recovery. However, evidence for their efficacy is varied and the methodological approaches and outcome measures used within the scientific literature are diverse.

Objectives

The aim of this scoping review is to provide a comprehensive overview of the effects of compression garments on commonly assessed outcome measures in response to exercise, including: performance, biomechanical, neuromuscular, cardiovascular, cardiorespiratory, muscle damage, thermoregulatory, and perceptual responses.

Methods

A systematic search of electronic databases (PubMed, SPORTDiscus, Web of Science and CINAHL Complete) was performed from the earliest record to 27 December, 2020.

Results

In total, 183 studies were identified for qualitative analysis with the following breakdown: performance and muscle function outcomes: 115 studies (63%), biomechanical and neuromuscular: 59 (32%), blood and saliva markers: 85 (46%), cardiovascular: 76 (42%), cardiorespiratory: 39 (21%), thermoregulatory: 19 (10%) and perceptual: 98 (54%). Approximately 85% (n = 156) of studies were published between 2010 and 2020.

Conclusions

Evidence is equivocal as to whether garments improve physical performance, with little evidence supporting improvements in kinetic or kinematic outcomes. Compression likely reduces muscle oscillatory properties and has a positive effect on sensorimotor systems. Findings suggest potential increases in arterial blood flow; however, it is unlikely that compression garments meaningfully change metabolic responses, blood pressure, heart rate, and cardiorespiratory measures. Compression garments increase localised skin temperature and may reduce perceptions of muscle soreness and pain following exercise; however, rating of perceived exertion during exercise is likely unchanged. It is unlikely that compression garments negatively influence exercise-related outcomes. Future research should assess wearer belief in compression garments, report pressure ranges at multiple sites as well as garment material, and finally examine individual responses and varying compression coverage areas.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40279-021-01604-9.

The Effect of Functional Biomechanics Garment for Walking

The purpose of this study was to investigate the effects of a functional biomechanics garment (FBG) with a lower extremity assist function. 32 healthy male participants were included in this study. Participants were divided into an FBG with taping function group (FBG group) and a compression garment group (CG group). Cadence (steps/min), step length (m), and usual walking speed (m/s) were measured as spatio-temporal data. Kinetics, kinematics data, and dynamic joint stiffness (DJS) of the lower extremity were calculated using a three-dimensional gait analysis system. The FBG group showed significantly faster walking speed (FBG, 1.54 ± 0.12 m/s; CG, 1.42 ± 0.15 m/s, p < 0.05) and reduced hip DJS in terminal stance (FBG, 0.033 ± 0.014 Nm/kg/degree; CG: 0.049 ± 0.016 Nm/kg/degree, p < 0.05) compared to the CG group. The FBG decreased hip DJS in the terminal stance and affected walking speed. The passive elastic moment generated by the high elasticity part of the hip joint front in the FBG supported the internal hip flexion moment. Therefore, our FBG has a biomechanical effect. The FBG may be useful as a tool to promote health activities.

A Systems Analysis Critique of Sport-Science Research

PURPOSE

The broad aim of sport-science research is to enhance the performance of coaches and athletes. Despite decades of such research, it is well documented that sport-science research lacks empirical evidence, and critics have questioned its scientific methods. Moreover, many have pointed to a research-practice gap, whereby the work undertaken by researchers is not readily applied by practitioners. The aim of this study was to use a systems thinking analysis method, causal loop diagrams, to understand the systemic issues that interact to influence the quality of sport-science research.

METHODS

A group model-building process was utilized to develop the causal loop diagram based on data obtained from relevant peer-reviewed literature and subject-matter experts.

RESULTS

The findings demonstrate the panoply of systemic influences associated with sport-science research, including the existence of silos, a focus on quantitative research, archaic practices, and an academic system that is incongruous with what it actually purports to achieve.

CONCLUSIONS

The emergent outcome of the interacting components is the creation of an underperforming sport-science research system, as indicated by a lack of ecological validity, translation to practice, and, ultimately, a research-practice gap.

Sports compression garments improve resting markers of venous return and muscle blood flow in male basketball players

BACKGROUND

The benefits associated with sports compression garments are thought to be closely related to enhanced blood flow. However, findings are equivocal, possibly due to heterogeneity in the techniques used for measuring blood flow, the garment types used, and the pressures applied. This study combined Doppler ultrasound and near-infrared spectroscopy technologies to provide the first comprehensive assessment of the effects of 3 sports compression garment types on markers of venous return and muscle blood flow at rest.

METHODS

Resting lower-limb blood flow measures (markers of venous return, muscle blood flow, and muscle oxygenation) of 22 elite, junior, male basketball players (age = 17.2 ± 0.9 years, mean ± SD) were assessed in 4 separate conditions: no compression (CON), compression tights (TIGHTS), compression shorts (SHORTS), and compression socks (SOCKS). Markers of venous return (cross-sectional area, time-averaged mean and peak blood flow velocity, and venous blood flow) were measured via Doppler ultrasound at the popliteal and common femoral veins. Muscle blood flow and muscle oxygenation were measured in the gastrocnemius medialis and vastus lateralis using near-infrared spectroscopy.

RESULTS

Popliteal markers of venous return were higher in TIGHTS compared to CON (p < 0.01) and SHORTS (p < 0.01), with SOCKS values higher compared with CON (p < 0.05). Common femoral vein markers of venous return were higher for all conditions compared to CON (p < 0.05), with TIGHTS values also higher compared to SOCKS (p < 0.05). Gastrocnemius medialis blood flow was higher for TIGHTS compared to CON (p = 0.000), SOCKS (p = 0.012), and SHORTS (p = 0.000), with SOCKS higher compared to SHORTS (p = 0.046). Vastus lateralis blood flow was higher for TIGHTS compared to CON (p = 0.028) and SOCKS (p = 0.019), with SHORTS also higher compared to CON (p = 0.012) and SOCKS (p = 0.005). Gastrocnemius medialis oxygenation was higher for TIGHTS compared to CON (p = 0.003), SOCKS (p = 0.033), and SHORTS (p = 0.003), with SOCKS higher compared to CON (p = 0.044) and SHORTS (p = 0.032). Vastus lateralis oxygenation was higher for TIGHTS compared to CON (p = 0.020) and SOCKS (p = 0.006).

CONCLUSION

Markers of venous return, muscle blood flow, and muscle oxygenation are increased with sports compression garments. TIGHTS are most effective, potentially because of the larger body area compressed.

Reduced post-exercise muscle microvascular perfusion with compression is offset by increased muscle oxygen extraction: Assessment by contrast-enhanced ultrasound

The microvasculature is important for both health and exercise tolerance in a range of populations. However, methodological limitations have meant changes in microvascular blood flow are rarely assessed in humans during interventions designed to affect skeletal muscle blood flow such as the wearing of compression garments. The aim of this study is, for the first time, to use contrast-enhanced ultrasound to directly measure the effects of compression on muscle microvascular blood flow alongside measures of femoral artery blood flow and muscle oxygenation following intense exercise in healthy adults. It was hypothesized that both muscle microvascular and femoral artery blood flows would be augmented with compression garments as compared with a control condition. Ten recreationally active participants completed two repeated-sprint exercise sessions, with and without lower-limb compression tights. Muscle microvascular blood flow, femoral arterial blood flow (2D and Doppler ultrasound), muscle oxygenation (near-infrared spectroscopy), cycling performance, and venous blood samples were measured/taken throughout exercise and the 1-hour post-exercise recovery period. Compared with control, compression reduced muscle microvascular blood volume and attenuated the exercise-induced increase in microvascular velocity and flow immediately after exercise and 1 hour post-exercise. Compression increased femoral artery diameter and augmented the exercise-induced increase in femoral arterial blood flow during exercise. Markers of blood oxygen extraction in muscle were increased with compression during and after exercise. Compression had no effect on blood lactate, glucose, or exercise performance. We provide new evidence that lower-limb compression attenuates the exercise-induced increase in skeletal muscle microvascular blood flow following exercise, despite a divergent increase in femoral artery blood flow. Decreased muscle microvascular perfusion is offset by increased muscle oxygen extraction, a potential mechanism allowing for the maintenance of exercise performance.

NIRS measures in pain and analgesia: Fundamentals, features, and function

Current pain assessment techniques based only on clinical evaluation and self-reports are not objective and may lead to inadequate treatment. Having a functional biomarker will add to the clinical fidelity, diagnosis, and perhaps improve treatment efficacy in patients. While many approaches have been deployed in pain biomarker discovery, functional near-infrared spectroscopy (fNIRS) is a technology that allows for non-invasive measurement of cortical hemodynamics. The utility of fNIRS is especially attractive given its ability to detect specific changes in the somatosensory and high-order cortices as well as its ability to measure (1) brain function similar to functional magnetic resonance imaging, (2) graded responses to noxious and innocuous stimuli, (3) analgesia, and (4) nociception under anesthesia. In this review, we evaluate the utility of fNIRS in nociception/pain with particular focus on its sensitivity and specificity, methodological advantages and limitations, and the current and potential applications in various pain conditions. Everything considered, fNIRS technology could enhance our ability to evaluate evoked and persistent pain across different age groups and clinical populations.

Wearing Compression Garment Enhances Central Hemodynamics? A Systematic Review and Meta-Analysis

Lee, DCW, Ali, A, Sheridan, S, Chan, DKC, and Wong, SHS. Wearing compression garment enhances central hemodynamics? a systematic review and meta-analysis . J Strength Cond Res XX(X): 000-000, 2020-Compression garments (CG) are believed to enhance exercise performance and recovery by improving central hemodynamic responses. However, evidence is inconclusive. We performed a systematic review and meta-analysis to determine the effect of wearing CG at rest or after a physiological challenge on central hemodynamic responses, including cardiac output, stroke volume (SV), heart rate (HR), systolic blood pressure, diastolic blood pressure (DBP), and systemic vascular resistance in healthy individuals. The English language searches of the electronic databases SPORTDiscus, MEDLINE, and Web of Science were conducted from November 2018-February 2019. The studies involved were limited to the following: (a) original articles; (b) randomized controlled trials; (c) monitoring of central hemodynamic responses (either at rest or after a physiological challenge: maximal exercise or orthostatic challenge); and (d) healthy individuals. Of the 786 studies identified, 12 were included in the systematic review and meta-analysis. Meta-analysis was performed by the restricted maximum likelihood method. The results indicated that the effect size (ES) of wearing CG on improving central hemodynamic responses was large overall (Hedges' g = 0.55) and was large in SV (Hedges' g = 1.09) and HR (Hedges' g = 0.65). Subgroup analysis showed that the ESs in "post-physiological challenge" was large in overall (Hedges' g = 0.98), SV (Hedges' g = 1.78), HR (Hedges' g = 1.10), and DBP (Hedges' g = 0.75). Their ESs in "at rest" were not significant in all central hemodynamic responses, apart from a significant medium ES observed in SV (Hedges' g = 0.44). Healthy individuals who wear CG have marked improvement in central hemodynamic responses, particularly after a physiological challenge. More pronounced effects of CG are observed in increasing SV and reducing HR.

Influence of a slow-start on overall performance and running kinematics during 6-h ultramarathon races

The aim of this study was to describe the pacing during a 6-h ultramarathon (race 1) and to investigate whether a slow-start affects performance, running kinematic changes, ratings of perceived exertion (RPE) and fatigue (ROF) (race 2). After a critical speed test, participants completed two 6-h ultramarathons. Race 1 (n = 16) was self-paced, whereas in race 2 (n = 10), athletes performed the initial 36 min at speeds 18% below the mean speed of the initial 36 min of race 1. In race 1, participants adopted an inverse sigmoid pacing. Contact times increased after 1 h, and flight times decreased after 30 min (all P ≤ .009); stride length reduced after 1 h 30 min (all P = .022), and stride frequency did not change. Despite the lower speeds during the first 10% of race 2, and higher speeds at 50% and 90%, performance remained unchanged (57.5 ± 10.2 vs. 56.3 ± 8.5 km; P = .298). However, RPE and ROF were lowered for most of race 2 duration (all P < .001). For the comparison of kinematic variables between races, data were normalised by absolute running speed at each time point from 1 h onwards. No differences were found for any of the kinematic variables. In conclusion, decreasing initial speed minimises RPE and ROF, but does not necessarily affect performance. In addition, running kinematic changes do not seem to be affected by pacing manipulation.

Acute and Delayed Neuromuscular Alterations Induced by Downhill Running in Trained Trail Runners: Beneficial Effects of High-Pressure Compression Garments

Introduction: The aim of this study was to examine, from a crossover experimental design, whether wearing high-pressure compression garments (CGs) during downhill treadmill running affects soft-tissue vibrations, acute and delayed responses in running economy (RE), neuromuscular function, countermovement jump, and perceived muscle soreness. Methods: Thirteen male trail runners habituated to regular eccentric training performed two separate 40-min downhill running (DHR, -8.5°) sessions while wearing either CGs (15-20 mmHg for quadriceps and calves) or control garments (CON) at a velocity associated with ∼55% of VO2max , with a set of measurements before (Pre-), after (Post-DHR), and 1 day after (Post-1D). No CGs was used within the recovery phase. Perceived muscle soreness, countermovement jump, and neuromuscular function (central and peripheral components) of knee extensors (KE) and plantar flexors (PF) were assessed. Cardiorespiratory responses (e.g., heart rate, ventilation) and RE, as well as soft-tissue vibrations (root mean square of the resultant acceleration, RMS Ar ) for vastus lateralis and gastrocnemius medialis were evaluated during DHR and in Post-1D. Results: During DHR, mean values in RMS Ar significantly increased over time for the vastus lateralis only for the CON condition (+11.6%). RE and cardiorespiratory responses significantly increased (i.e., alteration) over time in both conditions. Post, small to very large central and peripheral alterations were found for KE and PF in both conditions. However, the deficit in voluntary activation (VA) was significantly lower for KE following CGs (-2.4%), compared to CON (-7.9%) conditions. No significant differences in perceived muscle soreness and countermovement jump were observed between conditions whatever the time period. Additionally, in Post-1D, the CGs condition showed reductions in neuromuscular peripheral alterations only for KE (from -4.4 to -7.7%) and perceived muscle soreness scores (-8.3%). No significant differences in cardiorespiratory and RE responses as well as countermovement jump were identified between conditions in Post-1D. Discussion: Wearing high-pressure CGs (notably on KE) during DHR was associated with beneficial effects on soft-tissue vibrations, acute and delayed neuromuscular function, and perceived muscle soreness. The use of CGs during DHR might contribute to the enhanced muscle recovery by exerting an exercise-induced "mechanical protective effect."

Muscle Oximetry in Sports Science: A Systematic Review

BACKGROUND

Since the introduction (in 2006) of commercially available portable wireless muscle oximeters, the use of muscle near-infrared spectroscopy (NIRS) technology is gaining in popularity as an application to observe changes in muscle metabolism and muscle oxygenation during and after exercise or training interventions in both laboratory and applied sports settings.

OBJECTIVES

The objectives of this systematic review were to highlight the application of muscle oximetry in evaluating oxidative skeletal muscle performance to sport activities and emphasize how this technology has been applied to exercise and training.

METHODS

Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed in a systematic fashion to search, assess and synthesize existing literature on this topic. The Scopus and MEDLINE/PubMed electronic databases were searched to 1 March 2017. Potential inclusions were screened against eligibility criteria relating to recreationally trained to elite athletes, with or without training programs, who must have assessed physiological variables monitored by commercial oximeters or NIRS instrumentation.

RESULTS

Of the 14,609 identified records, only 57 studies met the eligibility criteria. This systematic review highlighted a number of key findings in 16 sporting activities. Overall, NIRS information can be used as a marker of skeletal muscle oxidative capacity and for analyzing muscle performance factors.

CONCLUSIONS

Although NIRS instrumentation is promising in evaluating oxidative skeletal muscle performance when used in sport settings, there is still the need for further instrumental development and randomized/longitudinal trials to support the detailed advantages of muscle oximetry utilization in sports science.

Effect of Compression Garments on the Development of Edema and Soreness in Delayed-Onset Muscle Soreness (DOMS)

Delayed-onset muscle soreness (DOMS), an ultrastructural muscle injury, is one of the most common reasons for impaired muscle performance. The purpose of this study was to investigate the influence of sport compression garments on the development of exercise-induced intramuscular edema in the context of DOMS. DOMS was induced in 15 healthy participants. The participants performed a standardized eccentric exercise of the calf muscles. Magnetic resonance imaging (MRI) was performed at baseline and 60h after exercise (T2-weighted signal intensity and T2 relaxation time was evaluated in each compartment and the intramuscular edema in the medial head of the gastrocnemius muscle was segmented). After the exercise, a conventional compression garment (18-21 mmHg) was placed on one randomized calf for 60h. The level of muscle soreness was evaluated using a visual analogue pain scale. T2-weighted signal intensity, T2 relaxation time and intramuscular edema showed a significant interaction for time with increased signal intensities/intramuscular edema in the medial head of the gastrocnemius muscle at follow-up compared to baseline. No significant main effect for compression or interaction between time and limb occurred. Further, no significant differences in the soleus muscle and the lateral head of the gastrocnemius muscle were noted between limbs or over time. After exercise, there was significantly increased muscle soreness in both lower legs in resting condition and when going downstairs and a decreased range of motion in the ankle joint. No significant difference was observed between the compressed and the non-compressed calf. Our results indicate that wearing conventional compression garments after DOMS has been induced has no significant effect on the development of muscle edema, muscle soreness, range of motion and calf circumference.

Lower Limb Sports Compression Garments Improve Muscle Blood Flow and Exercise Performance During Repeated-Sprint Cycling

Purpose: Evidence supporting the use of lower-limb compression garments during repeated-sprint exercise (RSE) with short rest periods, where performance will rely heavily on aerobic metabolism, is lacking. Methods: A total of 20 recreationally active participants completed 2 cycling RSE sessions, with and without lower-limb compression tights. The RSE session consisted of 4 sets of 10 × 6-s maximal sprints on a wind-braked cycle ergometer, interspaced by 24 s of recovery between bouts and 2 min of recovery between sets. Muscle oxygen consumption () of, and blood flow (mBF) to, the right vastus lateralis muscle was measured during exercise using near-infrared spectroscopy and venous/arterial occlusions of the right lower limb. Cycling performance, oxygen consumption (), heart rate, and capillary blood samples (lactate, pH, bicarbonate, and base excess) were also measured/taken throughout the session. Results: Compared with control, peak power (40.7 [19.9] W; mean ± 95% confidence intervals) and mBF (0.101 [0.061] mL·min−1·100 g−1) were higher, and heart rate (2  [1] beats/min) was lower, when participants wore compression (P < .05). , , blood lactate, and heart rate increased as a result of exercise (P < .05), with no differences between conditions. Similarly, blood pH, bicarbonate, and base excess decreased as a result of exercise (P < .05), with no difference between conditions. Conclusions: Wearing lower-limb compression tights during RSE with short intervals of rest improved cycling performance, vastus lateralis mBF, and heart rate. These results provide novel data to support the notion that lower-limb compression garments aid RSE performance, which may be related to local and/or central blood flow.

Effects of a capacitive-resistive electric transfer therapy on physiological and biomechanical parameters in recreational runners: A randomized controlled crossover trial

OBJECTIVES

This study compared the effects of a capacitive-resistive electric transfer therapy (Tecar) and passive rest on physiological and biomechanical parameters in recreational runners when performed shortly after an exhausting training session.

DESIGN

Randomized controlled crossover trial.

SETTING

University biomechanical research laboratory.

PARTICIPANTS

Fourteen trained male runners MAIN OUTCOME MEASURES: Physiological (running economy, oxygen uptake, respiratory exchange ratio, ventilation, heart rate, blood lactate concentration) and biomechanical (step length; stride angle, height, frequency, and contact time; swing time; contact phase; support phase; push-off phase) parameters were measured during two incremental treadmill running tests performed two days apart after an exhaustive training session.

RESULTS

When running at 14 km/h and 16 km/h, the Tecar treatment group presented greater increases in stride length (p < 0.001), angle (p < 0.05) and height (p < 0.001) between the first and second tests than the control group and, accordingly, greater decreases in stride frequency (p < 0.05). Physiological parameters were similar between groups.

CONCLUSIONS

The present study suggests that a Tecar therapy intervention enhances biomechanical parameters in recreational runners after an exhaustive training session more than passive rest, generating a more efficient running pattern without affecting selected physiological parameters.