Backward Running Research Articles

An evaluation of physical performance in collegiate athletes: A randomized controlled trial comparing backward and forward running

BackgroundBackward running (BR) and forward running (FR) activate distinct neuromuscular pathways and utilize differing biomechanical principles. Although FR is a well-established training modality, the potential advantages of BR for enhancing athletic performance and mitigating injury risk necessitate further exploration. Moreover, there exists a paucity of experimental data comparing these modalities in collegiate athlete populations. PurposeThis study sought to quantify the differential effects of BR intervention, FR intervention, and no intervention on agility, power, and speed performance in collegiate athletes. MethodsThirty collegiate athletes (Aged 18–28 years) were randomly allocated to the BR group (n = 10), FR group (n = 10), and an absolute control (CON) group (n = 10). The BR and FR groups performed running sessions on a treadmill for matched time and intensity biweekly for eight weeks. All athletes were assessed for agility, speed, and power performance before and after the intervention. ResultsResults revealed a significant main effect of time (p < 0.05) and significant group × time interactions (p < 0.05) for all outcomes, mean difference data showed BR outperformed FR & CON in countermovement jump (CMJ) (p < 0.05). For the 10-m sprint performance, a between-group difference was identified. A post-hoc Bonferroni test showed that the BR group performed better than the CON group (p = 0.02) but was not statistically different from the FR group (p > 0.05). ConclusionsBR intervention led to greater gains in CMJ performance and improved 10-m sprint performance compared to the control group, with little improvement compared to the FR group based on the mean difference data.

Comparison between backward, forward, and combined running training on performance of recreationally active young men

The study verified the effects of backward running training (BRT), forward running training (FRT), and combined backward/forward running training (BFRT), prescribed by Vpeak, on performance in 5-km running, countermovement jump, 20-m sprint, and the agility T-test, in thirty-three recreationally active young men. Thirty-three men (age 27.7 ± 4.8 years) were randomly assigned to one of three training groups (BRT; FRT; BFRT) and performed the following tests: 5-km running, vertical jump, 20-m sprint, agility performance, pre- and post-five weeks of running training. The normality of the data was verified by the Shapiro-Wilk test and the comparisons between groups and moments were performed by mixed ANOVA for repeated measures, followed by Bonferroni’s post hoc; the percentage of variation and the effect size (ES) were calculated. A significance level of P &lt; 0.05 was adopted. All groups improved 5-km (P = 0.01) performance at post-training. The Vpeak (P &lt; 0.01) and duration of the incremental test (P &lt; 0.01) increased significantly in all groups after training. The Vpeak_BR increased significantly in the BRT and BFRT groups. CMJ jump height increased significantly for the FRT (P &lt; 0.01) and BFRT (P &lt; 0.05) groups. In the agility T-test there was a significant moment effect (P &lt; 0.01) on the performance time. In conclusion, the inclusion of BRT sessions into FRT, prescribed based on Vpeak_BR and Vpeak_FR, leads to improvements in 5-km endurance running performance in recreationally active young men. Thus, it is suggested that BRT prescribed by Vpeak_BR could be more widely incorporated into FRT as a training method to obtain the same results in endurance performance as FRT alone.

Comparison between backward, forward, and combined running training on performance of recreationally active young men

The study verified the effects of backward running training (BRT), forward running training (FRT), and combined backward/forward running training (BFRT), prescribed by Vpeak, on performance in 5-km running, countermovement jump, 20-m sprint, and the agility T-test, in thirty-three recreationally active young men. Thirty-three men (age 27.7 ± 4.8 years) were randomly assigned to one of three training groups (BRT; FRT; BFRT) and performed the following tests: 5-km running, vertical jump, 20-m sprint, agility performance, pre- and post-five weeks of running training. The normality of the data was verified by the Shapiro-Wilk test and the comparisons between groups and moments were performed by mixed ANOVA for repeated measures, followed by Bonferroni’s post hoc; the percentage of variation and the effect size (ES) were calculated. A significance level of P &lt; 0.05 was adopted. All groups improved 5-km (P = 0.01) performance at post-training. The Vpeak (P &lt; 0.01) and duration of the incremental test (P &lt; 0.01) increased significantly in all groups after training. The Vpeak_BR increased significantly in the BRT and BFRT groups. CMJ jump height increased significantly for the FRT (P &lt; 0.01) and BFRT (P &lt; 0.05) groups. In the agility T-test there was a significant moment effect (P &lt; 0.01) on the performance time. In conclusion, the inclusion of BRT sessions into FRT, prescribed based on Vpeak_BR and Vpeak_FR, leads to improvements in 5-km endurance running performance in recreationally active young men. Thus, it is suggested that BRT prescribed by Vpeak_BR could be more widely incorporated into FRT as a training method to obtain the same results in endurance performance as FRT alone.

The effects of backward vs. forward running training on measures of physical fitness in young female handball players.

This study examined the effects of an 8-week backward running (BR) vs. forward running (FR) training programmes on measures of physical fitness in young female handball players. Twenty-nine players participated in this study. Participants were randomly assigned to a FR training group, BR training group, and a control group. Within-group analysis indicated significant, small-to-large improvements in all performance tests (effect size [g] = 0.36 to 1.80), except 5-m forward sprint-time in the BR group and 5- and 10-m forward sprint-time in the FR group. However, the CG significantly decreased forward sprint performance over 10-m and 20-m (g = 0.28 to 0.50) with no changes in the other fitness parameters. No significant differences in the amount of change scores between the BR and FR groups were noted. Both training interventions have led to similar improvements in measures of muscle power, change of direction (CoD) speed, sprint speed either forward or backward, and repeated sprint ability (RSA) in young female handball players, though BR training may have a small advantage over FR training for 10-m forward sprint time and CoD speed, while FR training may provide small improvements over BR training for RSAbest. Practitioners are advised to consider either FR or BR training to improve various measures of physical fitness in young female handball players.

The combined influence of body weight support and running direction on self-selected movement patterns

We investigated metabolic costs, muscle activity, and perceptual responses during forward and backward running at matched speeds at different body weight support (BWS) conditions. Participants ran forward and backward on a lower body positive pressure treadmill at 0%BWS, 20%BWS, and 50%BWS conditions. We measured oxygen uptake, carbon dioxide production, heart rate, muscle activity, and stride frequency. Additionally, we calculated metabolic cost of transport. Furthermore, we used rating of perceived exertion and feeling scale to investigate perceptual responses. Feeling scale during running was higher with increasing BWS (0–50%BWS), regardless of running direction (p < 0.05). Oxygen uptake, heart rate, and metabolic cost of transport were influenced by the interaction of running direction and BWS (p < 0.01). For example, metabolic cost of transport during backward running was greater than when running forward only when running at 0%BWS (i.e., 4.4 ± 1.1 and 5.8 ± 1.4 J/kg/m for forward and backward running, respectively: p < 0.001). However, rectus femoris muscle activity, stride frequency, and rating of perceived exertion during backward running were averages of 113.5%, 11.3%, and 2.8 rankings greater than when running forward, respectively, regardless of BWS (p < 0.001). We interpret our observations to indicate that environment (in the context of effective body weight) is a critical factor that determines self-selected movement patterns during forward and backward running.

Experimental investigation of the acoustic emission of an electrically driven propeller in thrust and recuperation mode in a wind tunnel

This paper presents the results of an experimental performance study of an electrically driven propeller in thrust and power recuperation mode in a subsonic wind tunnel. Using the reverberation chamber method, acoustic measurements were performed to evaluate them as a reference in relation to the performance data obtained. The three approaches to recuperation were investigated: Fixed pitch propeller at speed reduction (case 1), controllable pitch propeller with negative angle of attack (case 2), and inverted, backward running propeller (case 3). Results show that in-flight recuperation can be optimized in terms of low noise emissions and generating shaft power from the flow efficiently by choosing the respective operating point. For the latter, case 3 shows the greatest potential for a two bladed propeller, while case 2 has the lowest noise emissions and might reach higher values in recuperated power by increasing the propeller blade number.

Dielectric Elastomer-Driven Bionic Inchworm Soft Robot Realizes Forward and Backward Movement and Jump

To produce multi-modal mobility in complicated situations is a significant issue for soft robots. In this study, we show the conception, construction, and operation of an inchworm-impersonating dielectric elastomer-activated soft robot. The robot is small and lightweight, weighing only 3.5 g, and measuring an overall 110 mm by 50 mm by 60 mm (length, width, and height). The three mobility modes for the robot are each equipped with a detailed mechanism. When the excitation voltage is 5 kV, the robot runs forward under a frequency of stimulation of 1–9 Hz, and its direction of motion changes to a backwards motion at &gt;10 Hz. When the excitation voltage of 5.5 kV is applied to the robot, the robot runs forward at 1–12 Hz frequency and moves in the opposite direction at 13 Hz, reaching the fastest reverse speed of 240 mm/s. When the excitation voltage rises to 6 kV, the robot reaches its fastest running speed of 270 mm/s at 14 Hz. Motivated by high voltage and high duty cycle, the robot can jump over obstacles of 5 mm. In order to assess the performance of backward running, the speed achieved by the robot under a 30% duty cycle and a 50% duty cycle was compared, as well as the speed of the robot with or without the use of a counterweight. The robot has a simpler design and construction than earlier soft robots of the same kind, as well as a quicker speed, a wider variety of movement modes, and other notable advantages.

Influence of speed on running strategies during forward and backward running with body weight support.

Running with body weight support (BWS) and backward running have been included in exercise programs. However, it is not known how running characteristics of forward and backward running with BWS are influenced by the deviation in the running speed from the preferred speed (PS). The purpose of this study was to investigate how metabolic cost, muscle activity, and perceptual responses of forward and backward running with BWS are influenced by the deviation in running speed from the PS. Eleven participants ran forward and backward at 0%BWS, 20%BWS, and 50%BWS conditions. The running speed conditions were set to their mode-specific PS, PS+10%, and PS-10%. We measured metabolic cost, muscle activity, stride frequency, rating of perceived exertion, and feeling scale. Metabolic cost, muscle activity (rectus femoris and gastrocnemius), and rating of perceived of exertion during running increased with increasing speed, regardless BWS and running direction (P<0.05). For example, a 10% increase in running speed from the PS produced averages of 7.1% and 7.7% increases in oxygen uptake and rectus femoris muscle activity, respectively. However, stride frequency during forward and backward running with BWS did not increase with increasing speed when running speed was manipulated around the PS (i.e., 10% increments: P>0.05), with the exception of forward running at 50%BWS. A 10% increase in running speed from the PS may be useful for individuals who are required to increase their metabolic cost, muscle activity, and perceptual responses during running, regardless of BWS and running direction.

Combined Plyometric and Short Sprint Training in U-15 Male Soccer Players: Effects on Measures of Jump, Speed, Change of Direction, Repeated Sprint, and Balance.

This study examined the effect of 8 weeks of biweekly combined plyometric and short sprint training into the typical within-season training schedule of youth male soccer players. Participants were allocated at random to an experimental group (EG; n = 17, age: 14.6 ± 0.5 years, body mass: 60.5 ± 7.1 kg, height: 1.64 ± 0.08 m, body fat: 11.3 ± 1.4%) and a control group (CG; n = 17, age: 14.6 ± 0.4 years, body mass: 61.0 ± 3.9 kg, height: 1.67 ± 0.05 m, body fat: 11.8 ± 1.4%). Measures obtained pre- and post-intervention included vertical and horizontal jump performances (i.e., squat jump (SJ), countermovement jump with aimed arms (CMJA), and five-jump test (FJT)) and sprint performances (i.e., 10 and 30 m sprint). In addition, change-of-direction ability (sprint with 90° Turns (S90°) and sprint 9–3–6–3–9 m with backward and forward running (SBF)), repeated shuttle sprint ability (RSSA), and dynamic balance performance (Y balance test) were measured pre- and post-intervention. The EG experienced higher jump (all p < 0.05; d ≥ 0.71), sprint (all p < 0.05; d ≥ 0.64), change-of-direction ability (all p < 0.05; d ≥ 0.66), RSSA (all parameters except the fatigue index p < 0.01; d ≥ 0.71), and dynamic balance (all p ≤ 0.05; d ≥ 0.50) improvement compared to the CG. Adding biweekly combined plyometric and short sprint training to standard training improves the athletic performance of youth male soccer players (under 15 (U15)).

Backward Running on a Negative Slope as a Treatment for Achilles Tendinopathy in Runners: A Feasibility Pilot Study.

Achilles tendinopathy (AT) is a common musculoskeletal injury among runners. Eccentric exercises are considered first-line treatment. However, during the early stages of rehabilitation, patients are usually instructed to stop running. Backward running (BR) on a negative slope provides a similar eccentric load while enabling ongoing physical activity; thus, it may be suggested as an alternative treatment. To determine the feasibility of a BR program as a treatment option for AT in runners. Prospective, single-arm feasibility study. Outpatient clinic. Recreational runners diagnosed with AT and referred to the Meuhedet Health Services Physical Therapy Clinic in Jerusalem, Israel, from September 2019 to February 2020. The patients completed a 5-week (9 sessions) rehabilitation program of supervised BR on a negatively inclined treadmill. Compliance with the program was evaluated by calculating the percentage of patients who completed the full protocol with no adverse events. Personal running-related goals were set before the program and were assessed following rehabilitation using the goal attainment scaling method. Forward-running time until the onset of relevant Achilles tendon pain, and the Victorian Institute of Sports Assessment Scale-Achilles were measured at baseline (T0), before treatment session 6 (T1), and after the last session (T2). Among the 15 patients recruited, 14 (93%), average age 48.8 (10.4) years (86% males), completed the full protocol with no adverse events. Almost all participants (85.7%) achieved their running-related functional goals. Postintervention, the median forward-running time increased from 52.5 (92.5) to 900 (522.5)seconds (P = .008, effect size = .858), and the median Victorian Institute of Sports Assessment Scale-Achilles score improved by 28 points (P = .003, effect size = .881). BR on a negative slope may be a feasible treatment method for runners suffering from AT. Future randomized control trials are required to further validate the efficacy of this method.

An 8-Week Program of Plyometrics and Sprints with Changes of Direction Improved Anaerobic Fitness in Young Male Soccer Players.

This study examined the effects of 8 weeks of twice-weekly combined plyometric and sprint with change-of-direction (CPSCoD) training into habitual training regimes of young male soccer players. Participants were randomly allocated to an experimental group (n = 17, age: 14.6 ± 0.44 years, body mass: 61.2 ± 7.34 kg, height: 1.67 ± 0.09 m, body fat: 11.2 ± 1.56%) and a control group (n = 16, age: 14.6 ± 0.39 years, body mass: 61.1 ± 3.96 kg, height: 1.67 ± 0.05 m, body fat: 11.8 ± 1.47%). Measures obtained pre- and post intervention included vertical and horizontal jump performance (i.e., squat jump (SJ), countermovement jump (CMJ), and standing long jump (SLJ)), and sprint performance (i.e., 5 m and 20 m sprint). In addition, Measures obtained pre- and post-intervention included change-of-direction ability (4 × 5 m sprint test (S 4 × 5 m) and sprint 9–3–6–3–9 m with backward and forward running (SBF)), repeated change of direction (RCoD), and static balance performance (stork balance test). The training group experienced superior jump (all p < 0.05; d ≥ 0.61), sprint (all p < 0.05; d ≥ 0.58), change-of-direction (CoD) ability (all p < 0.05; d ≥ 0.58), RCoD (all parameters except the fatigue index p < 0.01; effect size (d) ≥ 0.71), and static balance (all p < 0.05; d ≥ 0.66) improvement. Adding twice-weekly CPSCoD training to standard training improves the anaerobic performance of U15 male soccer players.

Effects of Combined Plyometric and Short Sprints Training on Athletic Performance of Male U19 Soccer Players.

This project investigated adding 8 weeks of biweekly plyometric and short sprints training into standard training in elite youth soccer players. An experimental group (EG, n = 18, age: 17.6 ± 0.6 years, body mass: 67.6 ± 5.8 kg, height: 1.75 ± 0.06 m, and body fat: 11.5 ± 1.6%) and control group (CG, n = 18, age: 17.5 ± 0.6 years, body mass: 68.8 ± 3.6 kg, height: 1.77 ± 0.04 m, and body fat: 11.7 ± 1.2%) participated. Pre-intervention and post-intervention measures were squat-jump (SJ), countermovement-jump (CMJ), standing long jump (SLJ), 5 and 20 m sprints, change-of-direction ability (4 × 5 m sprint test [S 4 × 5 m] and sprint 9-3-6-3-9 m with backward and forward running [SBF]), repeated change of direction (RCOD), and static balance (the stork balance test). For all parameters, significant (p < 0.001, > 0.10) time and interaction (group × time) effects were observed. For three parameters (SBF, RCOD fastest time, and SLJ) no significant group effects were observed. The EG consistently showed a significantly higher performance level than the CG and a higher amount of effect sizes d (EG: drange: 1.27–2.61; CG: drange: 0.13–0.79) as an indicator for the development of performance between pre-intervention and post-intervention measures. Adding biweekly plyometric and short sprint training to standard training improves the athletic performance of young soccer players. Such plyometric and short sprint training conditioning can be highly recommended as part of the annual short training program for male elite under-19 (U19) soccer players.

Wearable Sensors Detect Movement Differences in the Portable Warrior Test of Tactical Agility After mTBI in Service Members.

Assessment of functional recovery of service members following a concussion is central to their return to duty. Practical military-relevant performance-based tests are needed for identifying those who might need specialized rehabilitation, for evaluating the progress of recovery, and for making return-to-duty determinations. One such recently developed test is the 'Portable Warrior Test of Tactical Agility' (POWAR-TOTAL) assessment designed for use following concussion in an active duty population. This agility task involves maneuvers used in military training, such as rapid stand-to-prone and prone-to-stand transitions, combat rolls, and forward and backward running. The effect of concussion on the performance of such maneuvers has not been established. The Institutional Review Board-approved study was conducted at Ft. Bragg, North Carolina, on 57 healthy control (HC) service members (SMs) and 42 well-matched SMs who were diagnosed with concussion and were referred for physical therapy with the intent to return to duty. Each study participant performed five consecutive trials of the POWAR-TOTAL task at full exertion while wearing inertial sensors, which were used to identify the constituent task maneuvers, or phases, and measure their durations. Statistical analyses were performed on durations of three main phases: (1) rising from prone and running, (2) lowering from vertical to prone, and (3) combat rolls. None of the three phases showed significant correlation with age (range 18-45 years) in either group. Gradual improvement in all three phase durations across five trials was observed in the HC group, but not in the concussed group. On average, control subjects performed significantly faster (P < .004 or less) than concussed subjects in all trials in the lowering and rolling phases, but less so in the rising/running phase. Membership in the concussed group had a strong effect on the lowering phase (Cohen's d = 1.05), medium effect on the rolling phase (d = 0.72), and small effect on the rising/running phase (d = 0.49). Individuals in the HC group who had a history of prior concussions were intermediate between the concussed group and the never-concussed group in the lowering and rolling phases. Duration of transitional movements (lowering from standing to prone and combat rolls) was better at differentiating individuals' performance by group (receiver operating characteristic area under the curve [AUC] = 0.83) than the duration of the entire POWAR-TOTAL task (AUC = 0.71). Inertial sensor analysis reveals that rapid transitional movements (such as lowering from vertical to prone position and combat rolls) are particularly discriminative between SMs recovering from concussion and their concussion-free peers. This analysis supports the validity of POWAR-TOTAL as a useful tool for therapists who serve military SMs.

Influence Of Running Direction On Metabolic Costs May Be Attenuated By Body Weight Support

During running on land, backward running produces greater metabolic and muscular demands than when running forward at the same speed. This type of research is important to identify the similarities and differences of forward and backward running, in order to best prescribe backward running as a cross-training stimulus for forward running. PURPOSE: The purpose of this study was to investigate the influence of running direction on metabolic, biomechanical, and perceptual demands during running at different levels of body weight support (BWS). METHODS: Thirteen participants ran forward and backward on a lower body positive pressure treadmill at 0%BWS, 20%BWS, and 50%BWS conditions at the same speed. We measured oxygen uptake (VO2), heart rate (HR), muscle activity (rectus femoris, biceps femoris, tibialis anterior, gastrocnemius), and stride frequency during the tests. Additionally, we calculated metabolic cost of transport (CoT). Furthermore, we used rating of perceived exertion (RPE) and feeling scale to investigate participants’ perceptual demands during the tests. VO2, HR, CoT, RPE, feeling scale, muscle activity, and stride frequency were analyzed using a 2 (directions) x 3 (BWS) repeated measures analysis of variance (α = 0.05). RESULTS: VO2, HR, and CoT were influenced by the interaction of BWS and running direction (P < 0.01). For example, CoT during backward running were greater than when running forward only when running at 0%BWS (4.5 ± 1.1 and 5.8 ± 1.4 J/kg/m in CoT for forward and backward running, respectively: P < 0.001). However, muscle activity from the rectus femoris, stride frequency, and RPE during backward running were averages of 113.5%, 11.3%, and 2.8 rankings greater than when running forward, respectively, regardless of BWS (P < 0.001). CONCLUSIONS: Backward running may require greater biomechanical and perceptual demands compared to forward running at the same speed, regardless of BWS. However, the influence of a change in running direction on metabolic demands may be attenuated by BWS. Supported by JSPS Grant Number 16 K01663.

Acceleration mechanics during forward and backward running: A comparison of step kinematics and kinetics over the first 20 m

ABSTRACT Backward running (BR) and forward running (FR) are unique movements utilized by athletes in many sports. Importantly, this investigation provides further insights on BR and benchmarking against more commonly researched FR capacity. Twenty-one collegiate soccer players (age 20.0 ± 0.8 years, body mass 65.6 ± 7.7 kg, body height 1.70 ± 0.07 m) performed maximal effort BR and FR along 20 m of in-ground force platforms. Step kinematics and kinetics were compared between BR and FR over four relative acceleration phases (BR = steps 1–6, 7–12, 13–18 and 19–23; FR = steps 1–4, 5–8, 9–12, 13–15). The primary findings of this study were that BR speeds were 29% slower than FR (p < 0.001), all step kinematics differed between BR and FR (p < 0.01), except contact time from the second to fourth step phases (p > 0.05), and most step kinetics were lower during BR (p < 0.05), with the exceptions of peak vertical force (p > 0.05). These findings indicate that lower running speeds over the acceleration phases of BR appear to be primarily due to lower horizontal ground reaction force application, resulting in shorter stride lengths and decreased flight times compared to FR.

Effects of a backward running training on backward peak velocity running, V̇O2max, vVO2max and 3 km forward running performance in male adults: a pilot study

Aims: The study aimed to evaluate the effects of a backward running (BR) training program prescribed by the peak backward running velocity (Vpeak_BR) on physiological variables and a 3 km forward running (FR) performance. Methods: Eight untrained running male adults in running took place in the study. All the participants underwent five weeks of BR training prescribed based on Vpeak_BR. They performed a maximal incremental test on the treadmill to determine the maximal oxygen uptake (V̇O2max) and the velocity associated with V̇O2max (vV̇O2max). The participants were also tested on the track field to determine the Vpeak_BR and undertook a 3 km FR performance. All initial assessments were also performed after the training period. Results: The results showed statistically significant improvements in 3 km FR performance (14.2 ± 1.2 min vs. 13.5 ± 1.0 min) and Vpeak_BR (8.0 ± 0.8 km·h−1 vs. 8.5 ± 0.5 km·h−1) after the training period. Conclusion: BR training effectively improved 3 km FR performance and Vpeak_BR, demonstrating that Vpeak_BR determined according to the protocol proposed in this study can be used for the prescription of BR training. Further, BR training represents an effective training method that can be inserted into an FR running training program.

Biomechanical and metabolic aspects of backward (and forward) running on uphill gradients: another clue towards an almost inelastic rebound

PurposeOn level, the metabolic cost (C) of backward running is higher than forward running probably due to a lower elastic energy recoil. On positive gradient, the ability to store and release elastic energy is impaired in forward running. We studied running on level and on gradient to test the hypothesis that the higher metabolic cost and lower efficiency in backward than forward running was due to the impairment in the elastic energy utilisation.MethodsEight subjects ran forward and backward on a treadmill on level and on gradient (from 0 to + 25%, with 5% step). The mechanical work, computed from kinematic data, C and efficiency (the ratio between total mechanical work and C) were calculated in each condition.ResultsBackward running C was higher than forward running at each condition (on average + 35%) and increased linearly with gradient. Total mechanical work was higher in forward running only at the steepest gradients, thus efficiency was lower in backward running at each gradient.ConclusionEfficiency decreased by increasing gradient in both running modalities highlighting the impairment in the elastic contribution on positive gradient. The lower efficiency values calculated in backward running in all conditions pointed out that backward running was performed with an almost inelastic rebound; thus, muscles performed most of the mechanical work with a high metabolic cost. These new backward running C data permit, by applying the recently introduced ‘equivalent slope’ concept for running acceleration, to obtain the predictive equation of metabolic power during level backward running acceleration.

Influence Of Running Speed On Muscle Activity During Backward Running With Body Weight Support

A change in running speed influences gait mechanics of running. PURPOSE: The purpose of this study was to investigate the influence of a change in running speed on muscle activity during forward and backward running at different body weight support (BWS) conditions. METHODS: Eleven participants (29.7 ± 12.3 years) ran forward and backward on a lower body positive pressure treadmill at 0%BWS, 20%BWS, and 50%BWS conditions. The running speed conditions consisted of forward and backward running at preferred speed (PS), PS+10%, and PS-10%. Muscle activity from the rectus femoris, biceps femoris, tibialis anterior, and gastrocnemius and stride frequency were measured. Muscle activity and stride frequency were analyzed using a 2 (running direction) x 3 (BWS) x 3 (running speed) repeated measures analysis of variance (α = 0.05). RESULTS: Muscle activity from the rectus femoris (P<0.01) and gastrocnemius (P<0.01) were significantly different between running speeds. For example, muscle activity from the rectus femoris (P<0.05) and gastrocnemius (P<0.05) during running at PS were significantly greater than when running at PS-10%, regardless of running direction and BWS. Furthermore, muscle activity from the rectus femoris (P<0.01) and gastrocnemius (P<0.05) during running at PS+10% were significantly greater than when running at PS, regardless of running direction and BWS. Stride frequency was influenced by the interaction of running direction and running speed (P<0.05). Using the pairwise comparisons, stride frequency during running at PS was significantly higher than that of running at PS-10% only when running forward and backward at 0%BWS (e.g., 84.5 strides/min and 82.0 strides/min for backward running at PS and PS-10% conditions, respectively: P<0.05). Furthermore, stride frequency during running at PS+10% was significantly higher than that of running at PS during forward and backward running at 0%BWS (P<0.05). CONCLUSIONS: Muscle activity from the rectus femoris and gastrocnemius during running may increase with increasing running speed, regardless of BWS and running direction. However, unique biomechanical strategies for the increased muscle activity from the lower extremity may exist for running with BWS.

The effects of stride frequency manipulation on physiological and perceptual responses during backward and forward running with body weight support.

We investigated the influence of a change in stride frequency on physiological and perceptual responses during forward and backward running at different body weight support (BWS) levels. Participants ran forward and backward at 0% BWS, 20% BWS, and 50% BWS conditions on a lower body positive pressure treadmill. The stride frequency conditions consisted of forward and backward running at preferred stride frequency (PSF), PSF + 10%, and PSF-10%. We measured oxygen uptake ([Formula: see text]O2), carbon dioxide production, heart rate (HR), muscle activity from the lower extremity, and rating of perceived exertion (RPE). Furthermore, we calculated the metabolic cost of transport (CoT). [Formula: see text]O2, HR, CoT, and muscle activity from the rectus femoris were significantly different between stride frequency conditions (P < 0.05). [Formula: see text]O2, HR, and CoT during running at PSF + 10% were significantly higher than when running at PSF, regardless of running direction and BWS (P < 0.05). However, RPE was not different between stride frequency conditions (P > 0.05: e.g., 12.8-13.8 rankings in RPE for backward running at 0% BWS). Manipulation of stride frequency during running may have a greater impact on physiological responses than on perceptual responses at a given speed, regardless of running direction and BWS. Individuals who need to increase their physiological demands during running may benefit from a 10% increase in stride frequency from the PSF, regardless of BWS and running direction.

Backward Running: Acute Effects on Sprint Performance in Preadolescent Boys.

The aim of this study was to examine the acute effect of backward running (BwR) during warm-up on a 20-m sprint of boys’ performance, compared to forward running (FwR). Fourteen recreationally active preadolescent boys (aged 12.5 ± 0.5 years) were examined in 3 protocols: warm-up (control condition), warm-up with 3 × 10 m additional BwR sprints and warm-up with 3 × 10 m additional FwR sprints. Participants were evaluated 4 minutes after each protocol on a 20-m sprint and intermediate distances, as well as the rate of perceived exertion (RPE). Sprint speed across 10-20 m was significantly higher for the BwR warm-up compared to the regular warm-up (p < 0.05) and a significantly higher RPE after the BwR and FwR protocols compared to the control condition was recorded (p < 0.05). No significant difference was detected across the distances 0–5, 5–10, 0–10 and 0–20 m. Although adding 3 × 10-m sprints of BwR or FwR after the warm-up did not enhance performance in a 20 m sprint of preadolescent boys, the positive effect of BwR across 10–20 m distance suggests that BwR could be an alternative means for enhancing performance for certain phases of a sprint for this age. However, preadolescent boys’ response to different sprint conditioning exercise stimuli and the optimization of rest time to maximize performance remain to be determined.