Effects of a verbal and visual feedback system on running technique, perceived exertion and running economy in female novice runners

The purpose of this study was to determine the effects of a verbal and visual feedback system on running technique, ratings of perceived exertion (RPE), and running economy. Twenty-two female novice runners were randomly assigned to experimental (n = 11) and control (n = 11) groups. The experimental subjects received verbal and visual feedback concerning their running technique prior to and during each training run. Training involved 15 20-min treadmill running sessions over a 5-week period. The control group adhered to the same training routine but did not receive feedback concerning their running technique. High-speed (100 Hz) photography was used to collect biomechanical data. A submaximal oxygen consumption test and Borg's RPE scale were used to collect data concerning running economy and perceived exertion, respectively. Statistical analysis using ANCOVA revealed that the proposed feedback system had a significant (P less than 0.01) effect on the experimental group's running technique by affecting the following desired changes relative to the control group: greater relative stride lengths, shorter support time, greater ankle dorsiflexion during support and greater knee flexion during support and non-support. There were no significant differences between the groups in submaximal VO2 or RPE. The results of this study suggest that verbal and visual feedback are effective means of eliciting modifications in running style in female novice runners. The link between modifications in running style and improvements in running economy and perceived exertion remains unclear.     

Effects of a verbal and visual feedback system on running technique,perceived exertion and running economy in female novice runners

The purpose of this study was to determine the effects of a verbal and visual feedback system on running technique, ratings of perceived exertion (RPE), and running economy. Twenty‐two female novice runners were randomly assigned to experimental (n = 11) and control (n = 11) groups. The experimental subjects received verbal and visual feedback concerning their running technique prior to and during each training run. Training involved 15 20‐min treadmill running sessions over a 5‐week period. The control group adhered to the same training routine but did not receive feedback concerning their running technique. High‐speed (100 Hz) photography was used to collect biomechanical data. A submaximal oxygen consumption test and Borg's RPE scale were used to collect data concerning running economy and perceived exertion, respectively. Statistical analysis using ANCOVA revealed that the proposed feedback system had a significant (P < 0.01) effect on the experimental group's running technique by affecting the following desired changes relative to the control group: greater relative stride lengths, shorter support time, greater ankle dorsiflexion during support and greater knee flexion during support and non‐support. There were no significant differences between the groups in submaximal VO₂ or RPE. The results of this study suggest that verbal and visual feedback are effective means of eliciting modifications in running style in female novice runners. The link between modifications in running style and improvements in running economy and perceived exertion remains unclear.     

Economy in track runners and orienteers during path and terrain running

The aims of the present study were to assess running economy in track runners and orienteers and to identify the factors responsible for any differences. The participants were 11 orienteers and 10 track runners of similar age, body mass, maximal oxygen uptake and training background. However, the orienteers included heavy terrain running in their daily training, whereas the track runners ran almost entirely on the roads and tracks. Maximal oxygen uptake and running economy were calculated during horizontal path running and during cross-country running in rough terrain with steep hills, using a telemetric system (K2, Cosmed, Italy). Running economy during path running was 217+/-12 and 212+/-14 ml x kg(-1) x km(-1) (mean +/- s) in the orienteers and the track runners, respectively. Running economy was impaired by 41-52% in heavy terrain (P < 0.05), and was less pronounced in the orienteers than in the track runners (88+/-18 vs 109+/-26 ml x kg(-1) x km(-1); P < 0.05). In conclusion, the better running economy of orienteers when changing from horizontal path to heavy terrain running could be an innate ability, or it could be speculated that specific training may improve running economy, indicating the importance of specific training for orienteers.     

Economy in track runners and orienteers during path and terrain running

The aims ofthe present study were to assess running economy in track runners and orienteers and to identify the factors responsible for any differences. The participants were 11 orienteers and 10 track runners of similar age, body mass, maximal oxygen uptake and training background. However, the orienteers included heavy terrain running in their daily training, whereas the track runners ran almost entirely on the roads and tracks. Maximal oxygen uptake and running economy were calculated during horizontal path running and during cross-country running in rough terrain with steep hills, using a telemetric system (K2, Cosmed, Italy). Running economy during path running was 217 +/- 12 and 212 +/- 14 ml.kg -1 .km -1 (mean +/- s) in the orienteers and the track runners, respectively. Running economy was impaired by 41-52% in heavy terrain (P ? 0.05), and was less pronounced in the orienteers than in the track runners (88 +/- 18 vs 109 +/- 26 ml.kg -1 .km -1 ; P ? 0.05). In conclusion, the better running economy of orienteers when changing from horizontal path to heavy terrain running could be an innate ability, or it could be speculated that specific training may improve running economy, indicating the importance of specific training for orienteers.     

Test–retest reliability of physiological parameters in elite junior distance runners following allometric scaling

This study aimed to quantify the intra-individual reliability of a number of physiological variables in a group of national and international young distance runners. Sixteen (8 male, 8 female) participants (16.7?±?1.4 years) performed a submaximal incremental running assessment followed by a maximal running test, on two occasions separated by no more than seven days. Maximal oxygen uptake (V?O_2max), speed at V?O_2max (km?h^?1), running economy and speed and heart rate (HR) at fixed blood lactate concentrations were determined. V?O_2max and running economy were scaled for differences in body mass using a power exponent derived from a larger cohort of young runners (n?=?42). Running economy was expressed as oxygen cost and energy cost at the speed associated with lactate turnpoint (LTP) and the two speeds prior to LTP. Results of analysis of variance revealed an absence of systematic bias between trials. Reliability indices showed a high level of reproducibility across all parameters (typical error [TE] ≤2%; intra-class correlation coefficient >0.8; effect size <0.6). Expressing running economy as energy cost appears to provide superior reliability than using oxygen cost (TE ～1.5% vs. ～2%). Blood lactate and HR were liable to daily fluctuations of 0.14–0.22?mmol?L^?1 and 4–5?beats?min^?1 respectively. The minimum detectable change values (95% confidence) for each parameter are also reported. Exercise physiologists can be confident that measurement of important physiological determinants of distance running performance are highly reproducible in elite junior runners.     

The effect of foot orthoses and insoles on running economy and performance in distance runners: A systematic review and meta-analysis

ABSTRACT

Foot orthoses and insoles are prescribed to runners, however their impact on running economy and performance is uncertain. The aim of this systematic review and meta-analysis was to determine the effect of foot orthoses and insoles on running economy and performance in distance runners. Seven electronic databases were searched from inception until June 2018. Eligible studies investigated the effect of foot orthoses or insoles on running economy (using indirect calorimetry) or running performance. Standardised mean differences (SMDs) were computed and meta-analyses were conducted using random effects models. Methodological quality was assessed using the Quality Index. Nine studies met the criteria and were included: five studies investigated the effect of foot orthoses on running economy and four investigated insoles. Foot orthoses were associated with small negative effects on running economy compared to no orthoses (SMD 0.42 [95% CI 0.17,0.72] p = 0.007). Shock absorbing insoles were also associated with negative effects on running economy, but an imprecise estimate (SMD 0.26 [95% CI ?0.33,0.84] p = 0.83). Quality Index scores ranged from 4 to 15 out of 17. Foot orthoses and shock absorbing insoles may adversely affect running economy in distance runners. Future research should consider their potential effects on running performance.     

The effect of attentional focus on running economy

Abstract

In research on motor control, the detrimental effect of an internal focus of attention on movement execution of well-learned motor skills is a frequently replicated finding. This experimental study was designed to determine whether this effect is observed with physiological variables during endurance exercise. We examined whether the focus of attention can influence running economy (oxygen consumption at a set running speed). Trained runners had to focus their attention on three different aspects while running on a treadmill. For three consecutive 10-min periods, runners concentrated on the running movement, on their breathing, and on their surroundings. Results showed an increased running economy in the external focus condition. In line with research on motor control, endurance sport also shows that an external focus of attention is better than an internal focus in terms of the physiological performance measure of oxygen consumption.     

不同水平中长跑运动员跑步能效的比较

目的:观察不同水平中长跑运动员跑步效能是否存在差异。方法:江苏田径队一、二线中长跑运动员,男性,各6名;便携式氧代谢测试仪器测试个人最好成绩平均速度下的跑步能效(RE,ml.kg-1.m-1)。结果:高水平组的跑步能效显著低于普通组的跑步能效(11.2±0.35,11.9±0.6,P=0.043)结论:本研究中高水平组运动员具有更好的运动节省能力。     

Longer-term effects of minimalist shoes on running performance,strength and bone density: A 20-week follow-up study*

This study investigated whether male runners improve running performance, running economy, ankle plantar flexor strength, and alter running biomechanics and lower limb bone mineral density when gradually transitioning to using minimalist shoes for 100% of weekly running. The study was a planned follow-up of runners (n?=?50) who transitioned to minimalist or conventional shoes for 35% of weekly structured training in a previous 6-week randomised controlled trial. In that trial, running performance and economy improved more with minimalist shoes than conventional shoes. Runners in each group were instructed to continue running in their allocated shoe during their own preferred training programme for a further 20 weeks while increasing allocated shoe use to 100% of weekly training. At the 20-week follow-up, minimalist shoes did not affect performance (effect size: 0.19; p?=?0.218), running economy (effect size: ≤?0.24; p?≥?0.388), stride rate or length (effect size: ≤?0.12; p?≥?0.550), foot strike (effect size: ≤?0.25; p?≥?0.366), or bone mineral density (effect size: ≤?0.40; p?≥?0.319). Minimalist shoes increased plantar flexor strength more than conventional shoes when runners trained with greater mean weekly training distances (shoe*distance interaction: p?=?0.036). After greater improvements with minimalist shoes during the initial six weeks of a structured training programme, increasing minimalist shoe use from 35% to 100% over 20 weeks, when runners use their own preferred training programme, did not further improve performance, running economy or alter running biomechanics and lower limb bone mineral density. Minimalist shoes improved plantar flexor strength more than conventional shoes in runners with greater weekly training distances.     

Thinking about your running movement makes you less efficient: attentional focus effects on running economy and kinematics

A number of studies have shown that attentional focus instructions can effect running economy. This study assessed spiroergometry, as well as running kinematics as a possible mechanism to explain these effects. Twelve runners had to focus their attention on either their running movement, their breathing or on a video while running on a treadmill at a set, submaximum speed. Spiroergometry and running kinematics were measured. Results revealed worse running economy in both internal focus conditions (breathing and movement) compared to the external focus condition (video), replicating previous findings. In addition, vertical oscillation during the running movement was elevated in the movement compared to the video condition, indicating a less efficient running style. No changes in kinematics were found for the breathing compared to the video condition. Therefore, consciously focusing on the running movement moves runners away from their optimised running pattern and leads to detriments in economy. The decreases in running economy in the breathing condition can be better explained by changes in breathing patterns.     

Differences in technique between sprinters and distance runners at equal and maximal speeds

In the finishing kick of a distance race, maximizing speed becomes the focus even if economy may be sacrificed. If distance runners knew how to alter their technique to become more sprint-like, this process could be more successful. In this study, we compared the differences in technique between sprinters and distance runners while running at equal and maximal speeds. Athletes consisted of 10 Division I distance runners, 10 Division I sprinters, and 10 healthy non-runners. They performed two tests, each consisting of a 60-m run on the track: Test 1 at a set pace of 5.81 m/s, while Test 2 was maximal speed. Video was collected at 180 Hz. Significant differences (P < 0.05) between the sprint and distance groups at maximal speeds were found in the following areas: speed, minimum hip angle, knee extension at toe-off, stride length, contact time, and recovery knee at touchdown. In Test 1, sprinters and distance runners displayed many of the same significant differences. The control group was similar to the distance group in both trials. As distance runners attempt to sprint, the desired adjustments do not necessarily occur. Distance runners may benefit from biomechanical interventions to improve running speed near the end of a race.     

Are gait characteristics and ground reaction forces related to energy cost of running in elite Kenyan runners?

The aim of this study was to determine whether gait cycle characteristics are associated with running economy in elite Kenyan runners. Fifteen elite Kenyan male runners completed two constant-speed running sets on a treadmill (12 km ·h^?1 and 20 km ·h^?1). VO₂ and respiratory exchange ratio values were measured to calculate steady-state oxygen and energy cost of running. Gait cycle characteristics and ground contact forces were measured at each speed. Oxygen cost of running at different velocities was 192.2 ± 14.7 ml· kg^?1· km^?1 at 12 km· h^?1 and 184.8 ± 9.9 ml· kg^?1· km^?1 at 20 km· h^?1, which corresponded to a caloric cost of running of 0.94 ± 0.07 kcal ·kg^?1·km^?1 and 0.93 ± 0.07 kcal· kg^?1· km^?1. We found no significant correlations between oxygen and energy cost of running and biomechanical variables and ground reaction forces at either 12 or 20 km· h^?1. However, ground contact times were ~10.0% shorter (very large effect) than in previously published literature in elite runners at similar speeds, alongside an 8.9% lower oxygen cost (very large effect). These results provide evidence to hypothesise that the short ground contact times may contribute to the exceptional running economy of Kenyan runners.     

Biomechanical Effects of Fatigue on 10,000 Meter Running Technique

Abstract

A study of the effect of fatigue on the mechanical characteristics of running during a 10,000 meter race was undertaken using high speed cinematography and a computer analysis technique. Eight highly skilled male subjects were filmed at four intervals throughout the event. An analysis of variance for trends was conducted for each of the dependent variables indicating the adjustments made by the runners that accompanied fatigue over the four stages of the event. Runners countered fatigue by changing sections of their total gait pattern (stride length, stride rate, segmental body positions) and reducing running velocity. Toward the end of the race the runners became less competent in the positioning of the foot and leg at foot-strike, which increased the potential for a retarding effect. A more extended lower limb increased the energy requirements of the recovery phase during the latter stages of the race. Fatigue caused these highly skilled runners to systematically alter their technique throughout the race. These adjustments, however, were not excessive.     

Running patterns for male and female competitive and recreational runners based on accelerometer data

The purpose of this study was to classify runners in sex-specific groups as either competitive or recreational based on center of mass (CoM) accelerations. Forty-one runners participated in the study (25 male and 16 female), and were labeled as competitive or recreational based on age, sex, and race performance. Three-dimensional acceleration data were collected during a 5-minute treadmill run, and 24 features were extracted. Support vector machine classification models were used to examine the utility of the features in discriminating between competitive and recreational runners within each sex-specific subgroup. Competitive and recreational runners could be classified with 82.63 % and 80.4 % in the male and female models, respectively. Dominant features in both models were related to regularity and variability, with competitive runners exhibiting more consistent running gait patterns, but the specific features were slightly different in each sex-specific model. Therefore, it is important to separate runners into sex-specific competitive and recreational subgroups for future running biomechanical studies. In conclusion, we have demonstrated the ability to analyze running biomechanics in competitive and recreational runners using only CoM acceleration patterns. A runner, clinician, or coach may use this information to monitor how running patterns change as a result of training.     

Joint stiffness and running economy during imposed forefoot strike before and after a long run in rearfoot strike runners

Research has focused on the effects of acute strike pattern modifications on lower extremity joint stiffness and running economy (RE). Strike pattern modifications on running biomechanics have mostly been studied while runners complete short running bouts. This study examined the effects of an imposed forefoot strike (FFS) on RE and ankle and knee joint stiffness before and after a long run in habitual rearfoot strike (RFS) runners. Joint kinetics and RE were collected before and after a long run. Sagittal joint kinetics were computed from kinematic and ground reaction force data that were collected during over-ground running trials in 13 male runners. RE was measured during treadmill running. Knee flexion range of motion, knee extensor moment and ankle joint stiffness were lower while plantarflexor moment and knee joint stiffness were greater during imposed FFS compared with RFS. The long run did not influence the difference in ankle and knee joint stiffness between strike patterns. Runners were more economical during RFS than imposed FFS and RE was not influenced by the long run. These findings suggest that using a FFS pattern towards the end of a long run may not be mechanically or metabolically beneficial for well-trained male RFS runners.     

Differences in technique between sprinters and distance runners at equal and maximal speeds

In the finishing kick of a distance race, maximizing speed becomes the focus even if economy may be sacrificed. If distance runners knew how to alter their technique to become more sprint-like, this process could be more successful. In this study, we compared the differences in technique between sprinters and distance runners while running at equal and maximal speeds. Athletes consisted of 10 Division I distance runners, 10 Division I sprinters, and 10 healthy non-runners. They performed two tests, each consisting of a 60-m run on the track: Test 1 at a set pace of 5.81 m/s, while Test 2 was maximal speed. Video was collected at 180 Hz. Significant differences (P < 0.05) between the sprint and distance groups at maximal speeds were found in the following areas: speed, minimum hip angle, knee extension at toe-off, stride length, contact time, and recovery knee at touchdown. In Test 1, sprinters and distance runners displayed many of the same significant differences. The control group was similar to the distance group in both trials. As distance runners attempt to sprint, the desired adjustments do not necessarily occur. Distance runners may benefit from biomechanical interventions to improve running speed near the end of a race.     

Initiating running barefoot: Effects on muscle activation and impact accelerations in habitually rearfoot shod runners

Runners tend to shift from a rearfoot to a forefoot strike pattern when running barefoot. However, it is unclear how the first attempts at running barefoot affect habitually rearfoot shod runners. Due to the inconsistency of their recently adopted barefoot technique, a number of new barefoot-related running injuries are emerging among novice barefoot runners. The aim of this study was therefore to analyse the influence of three running conditions (natural barefoot [BF], barefoot with a forced rearfoot strike [BRS], and shod [SH]) on muscle activity and impact accelerations in habitually rearfoot shod runners. Twenty-two participants ran at 60% of their maximal aerobic speed while foot strike, tibial and head impact accelerations, and tibialis anterior (TA), peroneus longus (PL), gastrocnemius medialis (GM) and gastrocnemius lateralis (GL) muscle activity were registered. Only 68% of the runners adopted a non-rearfoot strike pattern during BF. Running BF led to a reduction of TA activity as well as to an increase of GL and GM activity compared to BRS and SH. Furthermore, BRS increased tibial peak acceleration, tibial magnitude and tibial acceleration rate compared to SH and BF. In conclusion, 32% of our runners showed a rearfoot strike pattern at the first attempts at running barefoot, which corresponds to a running style (BRS) that led to increased muscle activation and impact accelerations and thereby to a potentially higher risk of injury compared to running shod.     

Moderate-domain pulmonary oxygen uptake kinetics and endurance running performance

The aims of this study were to determine if the primary time constant (tau) for oxygen uptake (VO2) at the onset of moderate-intensity treadmill exercise is related to endurance running performance, and to establish if tau could be considered a determinant of endurance running performance. Thirty-six endurance trained male runners performed a series of laboratory tests, on separate days, to determine maximal oxygen uptake (VO2max), the ventilatory threshold (VT) and running economy. In addition, runners completed six transitions from walking (4 km x h-1) to moderate-intensity running (80% VT) for the determination of the VO2 primary time constant and mean response time. During all tests, pulmonary gas-exchange was measured breath-by-breath. Endurance running performance was determined using a treadmill 5-km time-trial, after which runners were considered as combined performers (n=36) and, using a ranking system, high performers (n=10) and low performers (n=10). Relationships between tau and endurance running performance were quantified using correlation coefficients (r). Stepwise multiple regression was used to determine the primary predictor variables of endurance running performance in combined performers. Moderate correlations were observed between tau, mean response time and endurance running performance, but only for the combined performers (r=-0.55, P=0.001 and r=-0.50, P=0.002, respectively). The regression model for predicting 5-km performance did not include tau or mean response time. The velocity at VO2max was strongly correlated to endurance running performance in all groups (r=0.72 - 0.84, P < 0.01) and contributed substantially to the prediction of performance. In conclusion, the results suggest that despite their role in determining the oxygen deficit and having a moderate relationship with endurance running performance, neither tau nor mean response time is a primary determinant of endurance running performance.     

Effects of a minimalist shoe on running economy and 5-km running performance

The purpose of this study was to determine if minimalist shoes improve time trial performance of trained distance runners and if changes in running economy, shoe mass, stride length, stride rate and footfall pattern were related to any difference in performance. Twenty-six trained runners performed three 6-min sub-maximal treadmill runs at 11, 13 and 15 km·h^?1 in minimalist and conventional shoes while running economy, stride length, stride rate and footfall pattern were assessed. They then performed a 5-km time trial. In the minimalist shoe, runners completed the trial in less time (effect size 0.20 ± 0.12), were more economical during sub-maximal running (effect size 0.33 ± 0.14) and decreased stride length (effect size 0.22 ± 0.10) and increased stride rate (effect size 0.22 ± 0.11). All but one runner ran with a rearfoot footfall in the minimalist shoe. Improvements in time trial performance were associated with improvements in running economy at 15 km·h^?1 (r = 0.58), with 79% of the improved economy accounted for by reduced shoe mass (P < 0.05). The results suggest that running in minimalist shoes improves running economy and 5-km running performance.     

增强髋关节力量的重要性——优秀女子短跑运动员秦旺萍的训练启示

以当代短跑训练理论为指导,运用文献资料、个案研究、实验等方法对江苏省女子优秀短跑运动员秦旺萍进行增强髋关节力量训练的跟踪研究。研究认为增强髋关节力量(尤其是伸髋力量)对优秀短跑运动员具有十分重要的意义,它是当代优秀短跑选手以髋为轴高速摆动技术的重要保证,在短跑力量训练中应引起足够的重视。