Using the variability of continuous relative phase as a measure to discriminate between healthy and injured runners

Several studies have used variability of continuous relative phase (CRP) to investigate overuse injuries, since low variability is thought to be related to running injuries. This study investigates whether the analysis of CRP variability leads to additional information about possible differences or similarities between healthy and injured runners. Further, a decision about future applications of CRP variability should be based on the ability to implement and interpret data. 18 healthy female runners (CO) and 18 female runners who suffered from iliotibial band syndrome (ITBS) were evaluated by calculating CRP variability for 4 coupling pairs. Besides analyzing continuous variability of CRP, we also averaged it for the whole stance phase and for four predefined stance phase intervals. Confidence intervals were displayed and independent t-tests for comparing the two groups were conducted. During initial and terminal stance phase as well as after heel-off an increase in CRP variability was detected for both groups of runners. In contrast, the foot flat period was characterized by stable joint coordination and a decrease in variability. This paper presents possible interpretations of CRP variability but no statistically significant differences in CRP variability were found between the two groups of runners. Despite the missing statistical significance, a relationship between high CRP variability and injury seems to be conceivable, since the injured runners demonstrated an increased variability for all couplings in the first half of the stance phase. Further application of CRP variability in biomechanical research is essential to determine whether a relationship exists between injury and coordination variability.     

An Examination of Metacognitive Strategy Use and Monitoring Skills by Competitive Middle Distance Runners

This study investigated metacognitive strategy use by competitive athletes. Specifically, it tested the extent to which competitive middle-distance runners rely upon internally-focused metacognitive strategies versus externally-focused thoughts when they compete. In addition, the link between strategic knowledge and the regulation of such strategies during a novel self-paced task was investigated. Division I collegiate runners from the Midwestern U.S. (M age = 19.6, SD = 1.23) provided written responses to inventories about strategy use and completed a performance task requiring them to monitor and adjust their running pace. Results indicated an overwhelming tendency for the competitive runners in this study to report internally-focused strategies as opposed to externally-focused thoughts. The bulk of the thoughts that runners reported focused on either (a) monitoring bodily processes and form or (b) information management strategies that related to race tactics during competition. Furthermore, evidence was found for a link between self-report strategic knowledge and the ability to regulate one's performance on the self-paced task.     

Perceived cardiac risks and beliefs about health and running in elite older runners

Beliefs about the perceived health benefits of exercise of 24 elite runners were compared on an objective measure of risk for coronary heart disease. Results showed a 4- to 6-fold increase in estimates of perceived risk as compared to the objective estimate of risk, suggesting that these runners held somewhat exaggerated beliefs about the health benefits of running. In addition, these beliefs remained stable over time.     

Relationships of coping styles with type of sport

The purpose of this study was to ascertain whether the type of sport is associated with coping styles. 80 athletes (weightlifters, runners, swimmers, and triathletes) were administered the Coping Inventory for Stressful Situations. Analysis showed weightlifters had a lower mean score on Avoidance coping than the other groups of athletes. Differences concerning sex and ability were found as well.     

Comparison of ankle kinematics and ground reaction forces between prospectively injured and uninjured collegiate cross country runners

Biomechanical comparative studies on running-related injuries have included either currently or retrospectively injured runners. The purpose of this study was to prospectively compare ankle joint and ground reaction force variables between collegiate runners who developed injuries during the cross country season and those who did not. Running gait analyses using a motion capture system and force platform were conducted on 19 collegiate runners prior to the start of their cross country season. Ten runners sustained running-related injuries and 9 remained healthy during the course of the season. Strike index, peak loading rate of the vertical ground reaction force, dorsiflexion range of motion (ROM), eversion ROM, peak eversion angle, peak eversion velocity, and eversion duration from the start of the season were compared between injury groups. Ankle eversion ROM and peak eversion velocity were greater in uninjured runners while peak eversion angle was greater in injured runners. Greater ankle eversion ROM and eversion velocity with lower peak eversion angle may be beneficial in reducing injury risk in collegiate runners. The current data may only be applicable to collegiate cross country runners with similar training and racing schedules and threshold magnitudes of ankle kinematic variables to predict injury risk are still unknown.     

Effects of running and other activities on moods

The purpose of this study was to compare the moods and mood variations of runners to those of aerobic dancers, weight-lifters, and nonexercising controls. The subjects, 70 undergraduates, were participants in a jogging and conditioning, a weight training, an aerobic dance, or an introductory psychology class. A time-series design was used in which all participants completed eight Profile of Mood State questionnaires over a 6-hr. period that centered on the time of the class. Four questionnaires were completed during the second week of classes and the other four about midsemester, approximately 6 wk. later. Runners had a significantly more positive mood profile than nonexercisers and a somewhat more positive one than weight-lifters, but those of runners and aerobic dancers were similar. Changes in moods across time in relation to activity and across semester suggest that exercise, particularly aerobic exercise, helps the regular participant not only to cope with stress but also to have a generally more positive feeling of well-being.     

“Look around while running!” Attentional focus effects in inexperienced runners

While attentional focus effects on running economy have been shown in different settings for trained athletes, it is unclear how attentional instructions should be formulated to improve running economy for inexperienced runners. The present study was designed to fill this gap and test attentional focus effects in runners with little running experience. An experimental design was implemented and participants ran 4 × 6 min at a slow and fixed running pace with different attentional instructions for each block (video, breathing, running movement, no instruction), while oxygen consumption was measured continuously. The results showed best running economy (lowest oxygen consumption) in the video compared with the breathing and movement condition which goes in line with effects for trained runners. Therefore, inexperienced runners can also profit from directing their attention externally and commonly taught principles such as focusing on the coordination of breathing and stride patterns should be reconsidered.     

A comparative biomechanical analysis of habitually unshod and shod runners based on a foot morphological difference

Running is one of the most accessible physical activities and running with and without footwear has attracted extensive attention in the past several years. In this study 18 habitually male unshod runners and 20 habitually male shod runners (all with dominant right feet) participated in a running test. A Vicon motion analysis system was used to capture the kinematics of each participant’s lower limb. The in-shoe plantar pressure measurement system was employed to measure the pressure and force exerted on the pressure sensors of the insole. The function of a separate hallux in unshod runners is analyzed through the comparison of plantar pressure parameters. Owing to the different strike patterns in shod and unshod runners, peak dorsiflexion and plantarflexion angle were significantly different. Habitually shod runners exhibited a decreased foot strike angle (FSA) under unshod conditions; and the vertical average loading rate (VALR) of shod runners under unshod conditions was larger than that under shod conditions. This suggests that the foot strike pattern is more important than the shod or unshod running style and runners need to acquire the technique. It can be concluded that for habitually unshod runners the separate hallux takes part of the foot loading and reduces loading to the forefoot under shod conditions. The remaining toes of rearfoot strike (RFS) runners function similarly under unshod conditions. These morphological features of shod and unshod runners should be considered in footwear design to improve sport performance and reduce injury.     

Perceived benefits of marathon running in males and females

The differences in both perceived benefits and attitudes toward running between male and female runners, and between runners who classified themselves as competitive runners (CR) or recreational runners (RR), was the focus of this study. Four-hundred and two runners completed the Ten-Minute Survey for Runners within two weeks of completing a marathon. RR, more so than CR, perceived greater benefits from running. However, CR expressed a more positive attitude toward running and its role in their lives than did RR. Men perceived running to be more beneficial to them than women. However, women, more so than men, felt running had a positive effect on self-image and their lives were richer because of running. Future research concerns on the effects of competition on the lives of women are explored.     

Temporal perception in closed-skill sports: An experimental study on expert swimmers and runners

The cognitive benefits of closed-skill sports practice have so far been scantily investigated. Here, we thus focused on the potential impact of swimming and running - two sports that highly rely on a precise control of timing - on time processing. To investigate the impact of these closed-skill sports on time perception and estimation, three groups of participants (for a total of eighty-four young adults) took part in the present study: expert swimmers, expert runners, and non-athletes. The ability to process temporal information in the milliseconds and seconds range was assessed through a time reproduction and a finger-tapping tasks, while a motor imagery paradigm was adopted to assess temporal estimation of sport performance in a wider interval range. We also employed the Vividness of Movement Imagery Questionnaire to assess the individual's ability of motor imagery. Results showed that closed-skill sports, specifically time-related disciplines, enhance motor imagery and time perception abilities. Swimmers were more accurate and consistent in perceiving time when compared to runners, probably thanks to the sensory muffled environment that leads these athletes to be more focused on the perception of their internal rhythm.     

A prospective comparison of lower extremity kinematics and kinetics between injured and non-injured collegiate cross country runners

Collegiate cross country runners are at risk for running related injuries (RRI) due to high training volume and the potential for aberrant lower extremity biomechanics. However, there is a need for prospective research to determine biomechanical risk factors for RRI. The purpose of this study was to prospectively compare ankle, knee, and hip kinematics and kinetics and ground reaction force characteristics between injured and non-injured cross country runners over a 14-week season. Biomechanical running analyses were conducted on 31 collegiate-cross country runners using a 3-dimensional motion capture system and force plate prior to the start of the season. Twelve runners were injured and 19 remained healthy during the course of the season. Peak external knee adduction moment (KAM), a surrogate for frontal plane knee loading, and peak ankle eversion velocity were greater in runners who sustained an injury compared to those who did not, and no differences were noted in ground reaction force characteristics, or hip kinematics and kinetics. Reducing the KAM and ankle eversion velocity may be an important aspect of preventing RRI.     

Inter-joint coordination patterns differ between younger and older runners

Older runners are at greater risk of certain running-related injuries. Previous work demonstrated that aging influences running biomechanics, and suggest a compensatory relation between changes in the proximal and distal joints. Previous comparisons of interjoint coordination strategies between young and older runners could potentially have missed relevant differences by averaging coordination measures across time.ObjectiveTo compare coordination strategies between male runners under the age of 30 to those over the age of 60.MethodsTwelve young (22 ± 3 yrs, 1.80 ± 0.07 m, 78.0 ± 12.1 kg) and 12 older (63 ± 3 yrs, 1.78 ± 0.06 m, 73.2 ± 15.8 kg) male runners ran at 3.35 m/s on an instrumented treadmill. Ankle frontal plane, tibial transverse plane, knee sagittal plane, and hip frontal plane motion were measured. Inter-joint coordination was calculated using a modified vector coding technique. Coordination patterns and variability time series were compared between groups throughout stance using ANOVA for circular data.ResultsAt the ankle, older runners use in-phase propulsion (inversion, tibia external rotation) pattern following midstance (46–47% stance) while young runners are still in an in-phase collapse pattern (eversion, tibia external rotation). In coordination of the knee and hip, older runners maintained an in-phase collapse pattern (knee flexion, hip adduction) approaching midstance (35–37% stance), while younger runners use an out of phase strategy (knee extension, hip adduction). In coordination of the ankle and hip in the frontal plane, older runners again maintained an in phase collapse pattern up to midstance (34–39% stance), while younger runners used an out of phase strategy (ankle inversion, hip adduction). Variability was similar between age groups.ConclusionOlder runners appear to display altered coordination patterns during mid-stance, which may indicate protective biomechanical adaptations. These changes may also have implications for performance in older runners.     

Bilateral asymmetry of running gait in competitive,recreational and novice runners at different speeds

The mechanisms and underlying causes of bilateral asymmetry among healthy runners of different levels remain unclear. This cross-sectional laboratory study aimed to investigate the effects of running speed and running experience or competitive level on bilateral symmetry during running. Eleven competitive runners, 9 recreational runners and 11 novice runners were recruited in this study. They ran on an instrumented treadmill for 3 min at each of 5 fixed speeds (8, 9, 10, 11 and 12 km/h) in a randomized order. Bilateral asymmetry was evaluated and quantified using symmetry index (SI) of temporal and kinetic parameters. Overall, SI ranged between 0.8% for stride time and 21.4% for vertical average loading rate. Significant speed effects were observed on SI of flight time (p = .012), which was significantly higher at 8 km/h than that of the other 4 speeds (p = .023, 0.005, 0.023 and 0.028, respectively). Group-by-speed interactions were detected on SI in time to peak vertical ground reaction force (p = .032) and vertical average loading rate (p = .002). The competitive runners presented linear reduction in the SI with increasing speed from 8 to 12 km/h (R² > 0.94); for the recreational runners, SI changed nonlinearly and presented a roughly U-shaped trend across speeds (R² > 0.88); and for the novice runners, changes of SI across speed were inconsistent and dependent on parameters of interest (R² > 0.64). Bilateral asymmetry was affected by both running speed and runners' running experience or competitive level. The competitive runners were found to run with a more symmetrical manner with a greater running speed, the recreational runners demonstrated the most symmetrical pattern at the critical speed, whereas the novice runners showed inconsistent trends.     

Runners and meditators: a comparison of personality profiles

Although both running and meditating have been considered as healthful and enlightening, no data have yet been published comparing the personality profiles of the two groups. A sample of 48 runners and 43 meditators, all males between the ages of 40 and 60, were given the Cattell 16 PF Test Profile and the results were compared. The meditators were significantly more assertive and enthusiastic than the runners. They also appear as Significantly less conscientious and controlled than the runners, as well as more experimenting and suspicious.     

Athletic background is related to superior trunk proprioceptive ability,postural control,and neuromuscular responses to sudden perturbations

Trunk motor control is essential for athletic performance, and inadequate trunk motor control has been linked to an increased risk of developing low back and lower limb injury in athletes. Research is limited in comparing relationships between trunk neuromuscular control, postural control, and trunk proprioception in athletes from different sporting backgrounds. To test for these relationships, collegiate level long distance runners and golfers, along with non-athletic controls were recruited. Trunk postural control was investigated using a seated balance task. Neuromuscular control in response to sudden trunk loading perturbations was measured using electromyography and kinematics. Proprioceptive ability was examined using active trunk repositioning tasks. Both athlete groups demonstrated greater trunk postural control (less centre of pressure movement) during the seated task compared to controls. Athletes further demonstrated faster trunk muscle activation onsets, higher muscle activation amplitudes, and less lumbar spine angular displacement in response to sudden trunk loading perturbations when compared to controls. Golfers demonstrated less absolute error and variable error in trunk repositioning tasks compared to both runners and controls, suggestive of greater proprioceptive ability. This suggests an interactive relationship between neuromuscular control, postural control, and proprioception in athletes, and that differences exist between athletes of various training backgrounds.     

Runners and Meditators: A Comparison of Personality Profiles

Although both running and meditating have been considered as healthful and enlightening, no data have yet been published comparing the personality profiles of the two groups. A sample of 48 runners and 43 meditators, all males between the ages of 40 and 60, were given the Cattell 16 PF Test Profile and the results were compared. The meditators were significantly more assertive and enthusiastic than the runners. They also appear as Significantly less conscientious and controlled than the runners, as well as more experimenting and suspicious.     

Side-to-side differences in overuse running injury susceptibility: a retrospective study

Despite the number of studies examining factors associated with overuse running injury, little is known about why an individual gets injured on a particular side of the body. Abnormal levels of several strength, structural, kinetic, and kinematic factors have been attributed to injury susceptibility. However, while most studies have compared the injured limb of injured runners to an arbitrary limb of healthy controls, there is some evidence to suggest that injury risk is related to characteristics on both sides of a runner. Therefore, the purpose of this study was to investigate how bilateral characteristics of strength, structural, kinetic, and kinematic factors relate to overuse injury. The first purpose was to compare these factors between the injured and uninjured limbs of runners with a history of injury on only one side of their bodies. The results showed that hip internal rotation range of motion and peak tibial acceleration were both elevated on the side with a history of injury. The second purpose was to compare asymmetry levels between the injured runners and runners who had never sustained a running-related injury. Asymmetry levels were similar between groups for all variables, which suggests that some level of asymmetry is normal. The final purpose of the study was to compare bilateral values of these factors between the injured and uninjured runners. The results showed that hip internal rotation range of motion, as well as the deviation from normal arch height index, were bilaterally elevated in the injured runners. Although peak tibial acceleration was different between sides of the injured runners, it was not bilaterally elevated compared to the uninjured runners. These results support the notion that injury risk may be related to risk factors on both sides.     

Effect of voluntary exercise on open-field behavior and on aggression in the spontaneously hypertensive rat (SHR)

In the present study we investigated the influence of voluntary exercise on exploratory behavior and on aggression in the spontaneously hypertensive rat (SHR). Twenty-four SHR (8 weeks old) were randomly assigned to either an exercise group or a sedentary control group. The animals in the exercise group exhibited a spontaneous wheel running activity of 5-6 km/day during 6 weeks. The characteristic hyperexploratory behavior of SHR was lowered in the exercise group (p less than .001) as compared to the control group. The runners also showed a tendency for less aggression. In the postexercise period, when the runners' wheels were locked, the exercise group had a significant rise in aggression (p less than .01) vs the controls. The exploratory behavior returned immediately to the level of the controls, but we found no further increase in any of the parameters measured. However, the runners showed a type of displaced aggression exhibited as digging and biting in the test cage. This evidence suggests that voluntary exercise lowers the hyperexploratory behavior and aggression in the SHR and that an abrupt stop in exercise gives an "abstinence" reaction.     

Ankle kinetics and plantarflexor morphology in older runners with different lifetime running exposures

Running promotes better cardiovascular health and has positive effects on the musculoskeletal system in older adults. However, older adults have lower ankle plantarflexor torques and positive powers during running, and exhibit changes in plantarflexor morphology than young adults. Since older runners who run as much as younger runners exhibit youthful ankle mechanical outputs, running exposure may preserve the locomotor factors that mediate running speed. The purpose of this study was to compare ankle mechanical output during running and plantarflexor morphological characteristics between older runners who have low or high lifetime running exposure. Ten older runners with low lifetime running exposure and nine older runners with high lifetime running exposure performed over-ground running trials at 3.0 m/s (±5%) while kinematic and ground reaction force (GRF) data were collected and used to compute joint angular kinetics. Right medial gastrocnemius morphological characteristics were assessed using ultrasonography at rest and during isometric contractions. Ankle torques, powers, and plantarflexor morphology were compared between groups. Older runners with different lifetime running exposures ran with similar ankle mechanical output (i.e. no effect of running exposure) (p > .05) and exhibited similar medial gastrocnemius morphology during isometric testing. The findings from this study demonstrate that lifetime running exposure does not appear to influence ankle mechanical output or plantarflexor morphology in middle-aged runners.