Passive Heating Increases Bench-Pull Power Output in Highly Trained Swimmers.

PURPOSE: Determine the effects of skin temperature change on bench-pull power following a passive warm-up intervention with highly trained swimmers using multiple heated clothing garments. METHODS: Using a crossover design, 8 high-performance swimmers (mean [SD]; age, 22.4 [4.4] y; body mass, 74.9 [8.1] kg; height, 1.79 [0.09] m; world record ratio, 107.3% [5.1%]) completed a pool-based warm-up followed by a 35-minute transition phase before completing 3 repetitions at 50% of 1-repetition maximum of the bench-pull exercise. During transition, swimmers wore either a warm (control) or a heated (heat) clothing condition. RESULTS: Following heating, mean skin temperature was 0.7 °C higher in heat (P = .011), though no change was seen in tympanic temperature. Bench-pull mean and peak power improved by 4.5% and 4.7% following heating, respectively. A large repeated-measures correlation was observed between skin temperature and mean (r [90% CI] = .94 [.65 to .99], P < .01) and peak (r [90% CI] = .89 [.45 to .98], P < .01) power output. Thermal sensation and comfort at all regions were higher with heating (P ≤ .02). CONCLUSION: Combined upper- and lower-limb passive heating can increase whole-body skin temperature and improve short-duration upper-limb power output during the bench-pull exercise. Improvements in power output were directly related to the skin temperature increase facilitated by the heated clothing.

Swimming performance, physiology, and post-activation performance enhancement following dryland transition phase warmup: A systematic review.

BACKGROUND: In swimming, the period between the end of the swimming warmup and the beginning of competition is critical to performance, here termed the transition phase. Several options are available during this phase, necessitating a systematic review to understand if optimal strategies exist. OBJECTIVES: To synthesise and critically evaluate the current literature investigating land-based warmup interventions on subsequent performance in competitive swimmers. METHODS: A search of three electronic databases (PubMed, EBSCO SPORTDiscus and Web of Science) was conducted to identify original studies until February 2022. Selection criteria dictated that (i) a control condition was used, (ii) participants were ≥ 15 years of age, (iii) a pool-based warmup was done prior to the land-based warmup. A total of 25 articles met the selection criteria. RESULTS: Reducing the transition phase duration by at least half led to consistently faster time-trial times of between 1.1-1.5% for all included studies. Passive warmups using clothing interventions resulted in mostly faster time-trial's of 0.4-0.8% with increases in skin temperature frequent, though little change occurred in core temperature. The methodology of passive respiratory warmups were vastly different with positive time-trial's effects ranging between 0.9-1.1% for two studies, though one reported no meaningful difference. Active warmups led to consistently faster time-trial's between 0.7-0.9%, though the unpinning factors are not clear. Warmups which combined passive and active options frequently led to faster time-trial's between 0.8-3%. Upper and combined limb post-activation performance enhancement led to mostly unfavourable time-trial changes. Lower limb exclusive protocols results were inconsistent, with limited beneficial effects on time-trial or start performance reported following plyometric protocols. However, there does appear merit in heavier loaded lower limb protocols. CONCLUSION: Each of a reduced transition phase length, and passive, active or combination warmup have demonstrated improvements in swimming performance. Conversely, PAPE protocols should be used with caution, especially when including the upper limbs.

Effects of Water Immersion on Squat and Split Squat Kinematics in Older Adults.

This study examined the effect of water immersion on trunk and lower limb kinematics during squat exercises in older participants. A total of 24 active older adults (71.4 ± 5.4 years) performed squats and split squats on land and while partially submerged in water. Inertial sensors (100 Hz) were used to record trunk and lower body kinematics. Water immersion increased the squat depth (squat: p = .028, d = 0.63 and split squat: p = .005, d = 0.83) and reduced the trunk flexion range (squat: p = .006, d = 0.76 and split squat: p < .001, d = 1.35) during both exercises. In addition, water immersion increased the hip range of motion during the split squat (p = .002, d = 0.94). Waveform analyses also indicated differences in the timing of the movements. These results showed that water-based exercise generates a different exercise outcome and appears to provide an alternative option for older adults, enabling exercisers to perform these tasks in a manner not possible on land.

Establishing the reliability of a novel battery of range of motion tests to enable evidence-based classification in Para Swimming.

OBJECTIVES: To evaluate the reliability of swimming-specific range of movement tests developed in order to permit evidenced-based classification in the sport of para swimming. DESIGN: Test-retest intra- and inter-examiner reliability. SETTING: International Swimming training camps and university exercise science departments. PARTICIPANTS: 42 non-disabled participants (mean age 23.2 years) and 24 Para swimmers (mean age 28.5 years). MAIN OUTCOME MEASURES: Intra- and inter-examiner reliability of a battery of novel active range of motion tests. RESULTS: Good to excellent intra-examiner reliability was found for the majority (32/34) of tests in non-disabled participants (ICC = 0.85-0.98). SEM values ranged from 1.18° to 6.11°. Similarly, good to excellent inter-examiner reliability was found for the majority (35/42) of tests in non-disabled participants (ICC = 0.85-0.98). SEM values range from 0.73° to 6.52°. Para swimmers exhibited significantly reduced range of motion compared to non-disabled participants. CONCLUSIONS: The large majority of ROM tests included in this novel battery were reliable both within and between examiners in non-disabled participants. The tests were found to differentiate between non-disabled participants and Para swimmers with hypertonia or impaired muscle power.

Limb symmetry during double-leg squats and single-leg squats on land and in water in adults with long-standing unilateral anterior knee pain; a cross sectional study.

BACKGROUND: The presence of pain during movement typically results in changes in technique. However, the physical properties of water, such as flotation, means that water-based exercise may not only reduce compensatory movement patterns but also allow pain sufferers to complete exercises that they are unable to perform on land. The purpose of this study was to assess bilateral kinematics during double-leg squats and single-leg squats on land and in water in individuals with unilateral anterior knee pain. A secondary aim was to quantify bilateral asymmetry in both environments in affected and unaffected individuals using a symmetry index. METHODS: Twenty individuals with unilateral knee pain and twenty healthy, matched controls performed body weight double- and single-leg squats in both environments while inertial sensors (100 Hz) recorded trunk and lower body kinematics. Repeated-measures statistics tested for environmental effects on movement depths and peak angles within the anterior knee pain group. Differences in their inter-limb symmetry in each environments was compared to the control group using analysis of variance tests. RESULTS: Water immersion allowed for greater movement depths during both exercises (double-leg squat: +7 cm, p = 0.032, single-leg squat: +9 cm, p = 0.002) for the knee pain group. The double-leg squat was symmetrical on land but water immersion revealed asymmetries in the lower body frontal plane movements. The single-leg squat revealed decreased hip flexion and frontal plane shank motions on the affected limb in both environments. Water immersion also affected the degree of lower limb asymmetry in both groups, with differences also showing between groups. CONCLUSIONS: Individuals with anterior knee pain achieved increased squat depth during both exercises whilst in water. Kinematic differences between the affected and unaffected limbs were often increased in water. Individuals with unilateral anterior knee pain appear to utilise different kinematics in the affected and unaffected limb in both environments.

Quantifying kinematic differences between land and water during squats, split squats, and single-leg squats in a healthy population.

Aquatic exercises can be used in clinical and sporting disciplines for both rehabilitation and sports training. However, there is limited knowledge on the influence of water immersion on the kinematics of exercises commonly used in rehabilitation and fitness programs. The aim of this study was to use inertial sensors to quantify differences in kinematics and movement variability of bodyweight squats, split squats, and single-leg squats performed on dry land and whilst immersed to the level of the greater trochanter. During two separate testing sessions, 25 active healthy university students (22.3±2.9 yr.) performed ten repetitions of each exercise, whilst tri-axial inertial sensors (100 Hz) recorded their trunk and lower body kinematics. Repeated-measures statistics tested for differences in segment orientation and speed, movement variability, and waveform patterns between environments, while coefficient of variance was used to assess differences in movement variability. Between-environment differences in segment orientation and speed were portrayed by plotting the mean difference ±95% confidence intervals (CI) throughout the tasks. The results showed that the depth of the squat and split squat were unaffected by the changed environment while water immersion allowed for a deeper single leg squat. The different environments had significant effects on the sagittal plane orientations and speeds for all segments. Water immersion increased the degree of movement variability of the segments in all exercises, except for the shank in the frontal plane, which showed more variability on land. Without compromising movement depth, the aquatic environment induces more upright trunk and shank postures during squats and split squats. The aquatic environment allows for increased squat depth during the single-leg squat, and increased shank motions in the frontal plane. Our observations therefore support the use of water-based squat tasks for rehabilitation as they appear to improve the technique without compromising movement depth.

A systematic review on research into the effectiveness of group-based sport and exercise programs designed for Indigenous adults.

OBJECTIVES: To evaluate research into the effectiveness of group-based sport and exercise programs targeting Indigenous adults on anthropometric, physiological and quality of life outcomes. DESIGN: A systematic review with quality assessment of study design. METHODS: A computer-based literature search of EBSCO, SPORTDiscus, CINAHL, Informit, Scopus, Web of Science, Medline, PubMed, Global Health, ProQuest and Discover databases was conducted. Methodological quality of individual articles was assessed using McMasters University Guidelines and Appraisal Forms for Critical Review for Quantitative Research. Results of the effectiveness of programs are then summarised. RESULTS: Six articles were identified with critical appraisal scores ranging from 6 to 12 (from a possible 15 points), with a mean score of 9.6. Five articles were of moderate to good quality. Significant improvements were observed in anthropometric, physiological and quality of life outcomes across all studies. Elements of successful group-based exercise and sport programs corresponded to global recommendations on physical activity for health for 18 to 64 year olds, and were implemented over a period of time ranging from 12 to 24 weeks to exhibit results, plus community consultation in developing programs and nutrition education. CONCLUSIONS: Group-based programs that include nutrition, exercise and/or sport components are effective in producing short to intermediate term health outcomes among Indigenous adults. Further high quality research, specifically on group-based modified sport programs for Indigenous adults that are culturally appropriate and aim to improve quality of life are needed.

Activity Profiles and Physiological Responses of Representative Tag Football Players in Relation to Playing Position and Physical Fitness.

This study determined the physical fitness, match-activity profiles and physiological responses of representative tag football players and examined the relationship between physical fitness and the match-activity profile. Microtechnology devices and heart rate (HR) chest straps were used to determine the match-activity profiles of sixteen tag football players for five matches during the 2014 Australian National Championships. The relationships between lower body muscular power, straight line running speed and Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2) and the match-activity profile were examined using Pearson's correlation coefficients. Outside players had greater lower body muscular power (ES = 0.98) and straight line running speed (ES = 1.03-1.18) than inside players, and also covered greater very high-speed running (VHSR) distance/min (ES = 0.67) and reached higher peak running speeds (ES = 0.95) during matches. Inside and outside players performed a similar number of repeated high-intensity effort (RHIE) bouts and reported similar mean and maximum efforts per RHIE bout. However, there were differences between playing positions for mean and maximal RHIE effort durations (ES = 0.69-1.15) and mean RHIE bout recovery (ES = 0.56). Inside and outside players also reported small to moderate differences (ES = 0.43-0.80) for times spent in each HR zone. There were a number of moderate to very large correlations between physical fitness measures and match-activity profile variables. This study found lower body muscular power, straight line running speed and Yo-Yo IR2 to be related to the match-activities of representative tag football players, although differences between inside and outside players suggest that athlete testing and training practices should be modified for different playing positions.

Influence of Yo-Yo IR2 Scores on Internal and External Workloads and Fatigue Responses of Tag Football Players during Tournament Competition.

The purpose of this study was to: a) identify changes in jump height and perceived well-being as indirect markers of fatigue, b) determine the internal and external workloads performed by players, and c) examine the influence of Yo-Yo IR2 on changes in jump height, perceived well-being and internal and external workloads during a tag football tournament. Microtechnology devices combined with heart rate (HR) chest straps provided external and internal measures of match work-rate and workload for twelve male tag football players during the 2014 Australian National Championships. Jump height and perceived well-being were assessed prior to and during the tournament as indirect measures of fatigue. Changes in work-rate, workload and fatigue measures between high- and low-fitness groups were examined based on players' Yo-Yo IR2 score using a median split technique. The low- and high-fitness groups reported similar mean HR, PlayerloadTM/min, and distance/min for matches, however the low-fitness group reported higher perceived match-intensities (ES = 0.90-1.35) for several matches. Further, the high-fitness group reported higher measures of tournament workload, including distance (ES = 0.71), PlayerloadTM (ES = 0.85) and Edwards' training impulse (TRIMP) (ES = 1.23) than the low-fitness group. High- and low-fitness groups both showed large decreases (ES = 1.46-1.49) in perceived well-being during the tournament, although jump height did not decrease below pre-tournament values. Increased Yo-Yo IR2 appears to offer a protective effect against player fatigue despite increased workloads during a tag football tournament. It is vital that training programs adequately prepare tag football players for tournament competition to maximise performance and minimise player fatigue.

Low-Load Very High-Repetition Resistance Training Attenuates Bone Loss at the Lumbar Spine in Active Post-menopausal Women.

This study determined the effect of 6 months of low-load very high-repetition resistance training on bone mineral density (BMD) and body composition in nonosteoporotic middle-aged and older women. Fifty healthy, active community-dwelling women aged 56-75 years took part in the two-group, repeated-measures randomized controlled trial. Participants either undertook 6 months of low-load very high-repetition resistance training in the form of BodyPump™ or served as control participants. Outcome measures included BMD at the lumbar spine, hip, and total body; total fat mass; fat-free soft tissue mass and maximal isotonic strength. Significant group-by-time interactions were found for lumbar spine BMD and maximal strength in favor of the BodyPump™ group. No favorable effects were found for hip BMD, total body BMD, total fat mass, or fat-free soft tissue mass. Three participants withdrew from the intervention group due to injury or fear of injury associated with training. Under the conditions used in this research, low-load very high-repetition resistance training is effective at attenuating losses in lumbar spine BMD compared to controls in healthy, active women aged over 55 years but did not influence hip and total body BMD or fat mass and fat-free soft tissue mass.

Low-load high-repetition resistance training improves strength and gait speed in middle-aged and older adults.

OBJECTIVES: To determine the effect of 26 weeks of low-load high-repetition resistance training (BodyPump™) on maximal strength, gait speed, balance and self-reported health status in healthy, active middle-aged and older adults. DESIGN: Two-group randomised control trial. METHODS: Sixty-eight apparently healthy, active adults aged over 55 years completed either 26 weeks of BodyPump™ training (PUMP) or served as control participants (CON). The BodyPump™ group (n = 32, age = 66 ± 4 years) trained twice per week for 26 weeks while the control group (n = 36, age = 66 ± 5 years) continued with their normal activities. Leg-press and Smith-machine bench-press one repetition maximum (1RM), gait speed, balance, and self-reported health status were all assessed at baseline and follow-up. RESULTS: Significant group-by-time interactions in favour of the BodyPump™ group were found for leg-press 1RM (PUMP + 13%, CON + 3%, p = 0.007, partial eta(2) = 0.11), Smith-machine bench-press 1RM (PUMP + 14%, CON +5%, p = 0.001, partial eta(2) = 0.18), normal gait speed (PUMP + 23%, CON +9 %, p = 0.028, partial eta(2) = 0.08) and single leg balance right (PUMP + 24%, CON - 7%, p = 0.006, partial eta(2) = 0.12). There were no group-by-time interactions for health status measures. Three participants in the BodyPump™ group withdrew from training due to injury or fear of injury related to training. CONCLUSIONS: Low-load high-repetition resistance training in the form of BodyPump™ is effective at improving maximal strength, gait speed and some aspects of standing balance in adults over 55 years. The training was well tolerated by the majority of participants.

Do the nutrition qualifications and professional practices of registered exercise professionals align?

Australia has approximately 26,000 registered exercise professionals (REP), in comparison with 3,379 accredited practicing dietitians (APD). The REP workforce has the potential to reach more than 10% of the Australian population but there is limited data on their educational background and professional behaviors with regards to nutritional counseling of clients. The purpose of this research was to determine if REPs are working within their scope of practice and if their qualifications align with their practice, specifically as it relates to nutrition advice. Using a cross sectional descriptive study design, a self-administered online survey of REPs was conducted over 5 months. REPs were recruited through electronic and social media using a snowballing technique. The study focused on education, nutrition advice, and sources of information. A total of 286 respondents completed the survey, including 13 with tertiary dietetic qualifications i.e., APDs. The nationally recognized industry Certificate III/IV in Fitness was the most common qualification. The majority of REPs responding (88%) were working outside of their professional scope of practice, offering individual nutrition advice to clients across fitness and medical issues. This was despite 40% of REPs undertaking no further training in nutrition since graduating, and primarily basing advice on use of readily accessible sources of nutrition information. It is recommended the nutrition advice provided to REPs during training be limited to general nonmedical nutrition information in accordance with nationally endorsed evidence based guidelines and that issues pertaining to scope of practice be addressed with onward referral to other health professionals be advocated.

Neuromuscular and perceptual fatigue responses to consecutive tag football matches.

PURPOSE: To examine the neuromuscular and perceptual fatigue responses to consecutive tag football matches played on the same day and determine the relationship between fatigue and match running performance. METHODS: Neuromuscular and perceptual fatigue responses of 15 national tag football players were assessed before and during the 2014 State of Origin tournament. Global positioning systems (GPS) provided data on players' match running performance, and a vertical-jump test and subjective questionnaire were used to assess players' neuromuscular and perceptual fatigue, respectively. RESULTS: There were small to moderate reductions in the majority of match-running-performance variables over consecutive matches, including distance (ES=-0.81), high-speed-running (HSR) distance (ES=-0.51), HSR efforts (ES=-0.64), and maximal accelerations (ES=-0.76). Prematch vertical jump was initially below baseline values before the first match (ES=0.68-0.88). There were no substantial reductions in vertical-jump performance from baseline values over consecutive matches, although there was a small decline from after match 2 to after match 3 (3.3%; ES=-0.45±0.62). There were progressive reductions in perceived well-being scores after matches 1 (ES=-0.38), 2 (ES=-0.70), and 3 (ES=-1.14). There were small to moderate associations between changes in fatigue measures and match running performance. CONCLUSIONS: Perceptual fatigue accumulates over consecutive tag football matches, although there were only marginal increases in neuromuscular fatigue. However, both neuromuscular and perceptual fatigue measures were found to contribute to reduced match running performance in the final match.

Twelve weeks of BodyBalance® training improved balance and functional task performance in middle-aged and older adults.

PURPOSE: The purpose of the study was to evaluate the effect of BodyBalance(®) training on balance, functional task performance, fear of falling, and health-related quality of life in adults aged over 55 years. PARTICIPANTS AND METHODS: A total of 28 healthy, active adults aged 66±5 years completed the randomized controlled trial. Balance, functional task performance, fear of falling, and self-reported quality of life were assessed at baseline and after 12 weeks. Participants either undertook two sessions of BodyBalance per week for 12 weeks (n=15) or continued with their normal activities (n=13). RESULTS: Significant group-by-time interactions were found for the timed up and go (P=0.038), 30-second chair stand (P=0.037), and mediolateral center-of-pressure range in narrow stance with eyes closed (P=0.017). There were no significant effects on fear of falling or self-reported quality of life. CONCLUSION: Twelve weeks of BodyBalance training is effective at improving certain balance and functional based tasks in healthy older adults.

The influence of upper-body strength on flat-water sprint kayak performance in elite athletes.

Dry-land strength training is a fundamental component for elite kayak performance. The aims of this research were 3-fold: 1st, to determine the relationship between performance time and strength scores for elite kayakers; 2nd, to identify how strength changes (gains or losses) over 3 training y relate with changes in performance time for elite kayakers; and 3rd, to compare the progression in performance times for elite athletes with the top 3 performers from the national championships. The performance data for 15 elite male and 10 elite female kayakers were collected over 2 y. This group was reduced to 9 men and 8 women in the 3rd and final year. There were direct and significant correlations between strength scores and performance times across the 3 y. Bench-press 1RM increased by 34.8% for men and 42.3% for women. Over the 3 seasons, mean 1000-m time decreased by approximately 4.8%, 500-m times decreased by 7.3% (women), and 200-m times decreased by 9.1%. The women's 500-m changed from 11.9% difference from medalists to within 1.1% during the 3 y. During the 3 y of this study a change in 1-repetitionmaximum (1RM) bench press of 13% for men and 6.5% in women coincided with a change in performance times of 1%. For 1RM pull-up a change of 10% in men and 2.3% in women coincided with a change in performance times of 1%.

Detection of illegal race walking: a tool to assist coaching and judging.

Current judging of race walking in international competitions relies on subjective human observation to detect illegal gait, which naturally has inherent problems. Incorrect judging decisions may devastate an athlete and possibly discredit the international governing body. The aim of this study was to determine whether an inertial sensor could improve accuracy, monitor every step the athlete makes in training and/or competition. Seven nationally competitive race walkers performed a series of legal, illegal and self-selected pace races. During testing, athletes wore a single inertial sensor (100 Hz) placed at S1 of the vertebra and were simultaneously filmed using a high-speed camera (125 Hz). Of the 80 steps analyzed the high-speed camera identified 57 as illegal, the inertial sensor misidentified four of these measures (all four missed illegal steps had 0.008 s of loss of ground contact) which is considerably less than the best possible human observation of 0.06 s. Inertial sensor comparison to the camera found the typical error of estimate was 0.02 s (95% confidence limits 0.01-0.02), with a bias of 0.02 (±0.01). An inertial sensor can thus objectively improve the accuracy in detecting illegal steps (loss of ground contact) and, along with the ability to monitor every step of the athlete, could be a valuable tool to assist judges during race walk events.

The lumbar and sacrum movement pattern during the back squat exercise.

An essential exercise for strength training of the lower limbs is the squat exercise. During this exercise, changes in lumbar lordosis are commonly used to indicate when the descent of the squat should cease, yet the behavior of the lumbar-scarum segments remains unclear. The purpose of this study was to quantify the lumbar-sacrum movements during the back squat, because the movement of the sacrum is influenced by the width of stance, this variable was also investigated. Thirty trained subjects, 18 men with 1 repetition maximum (1RM) squat of 123% (13.9%) of bodyweight and 12 women with 1RM squat of 93% (15.6%), performed a set of narrow and wide stance squats, each carrying an additional 50% of body weight as load. The timing and movement of the lumbar angle (T12/L1), sacrum angle (L5/S1), and lumbar flexion angle (lumbar lordosis) were measured in 3 dimensions for the ascent and decent phases. Men and women achieved similar lumbar angles for both width of stance and phase. Sacrum angles, lumbar flexion angles, and timing differed significantly (p < 0.05) between gender and width of stance. The lumbar flexion range during the descent phase for women in narrow and wide stance was 12.9° and 12.6°, respectively; for men, this range was significantly (p < 0.05) larger at 26.3° and 25.4°, respectively. Men and women developed different movement patterns for the squatting movement, and therefore, this needs to be considered in strength development and screening procedures. The lumbar spine became kyphotic as soon as a load was placed on the shoulders, and any teaching cues to maintain a curved lumbar spine when squatting must be questioned.

Quantifying the movement and the influence of load in the back squat exercise.

The squat is used extensively in strength and conditioning, physical therapy, rehabilitation, and fitness programs. However, the movement pattern of the hip and knee is still relatively unknown, in particular, the timing of when maximum angles is reached. The purpose of this study was to quantify the hip and knee movements of the squat and establish if load alters these movements. Twenty-eight subjects (16 men and 12 women) performed 2 sets of 8 squats. Load was applied in random order as no additional weight (body weight [BW]) or an additional load of 50% of the subject's weight (BW+50%). Joint angles and time for hip and knee, as well as forward knee, displacement in the descent and ascent phases were measured with significance at p<0.05. Regardless of gender, phase, and load, all subjects achieved their maximum hip and knee angles within 2% of the deepest position. Load significantly increased the flexion angle at the hip and knee joints in men. The knees movement forward of the toes ranged from 63.8 to 64.7 mm in men and 93.2 to 96.6 mm in women. A significant difference in the timing of when the maximum forward knee movement occurred was observed because of gender. The overriding factor for the practical prescription of squat technique was regardless of load, gender, or phase; the maximum angles of the hip and knee are reached almost simultaneously at the bottom of the squat. Furthermore, for all subjects, the knee moved forward of the toes when squatting with men reaching their maximum forward knee position around 84% of the descent phase, whereas this occurred for women around 93%.

Identifying symmetry in running gait using a single inertial sensor.

Running gait has been shown to alter due to changes in intensity. It was hypothesised that a sacral mounted single inertial sensor could identify the centre of mass (COM) vertical accelerations. This study aimed to validate this new technique against a criterion measure and to determine the influence of changes in running intensity on COM vertical acceleration and the symmetry of COM vertical acceleration between left and right steps. Ten athletes ran for 5min at their self-selected pace, plus 1km/h above and below this velocity. Validity of the single inertial sensor was determined by comparing COM vertical acceleration against that measured with a six-camera infrared system. Large correlation (r=0.96), a small typical error of estimate (1.84), and mean bias (0.02) were found between the two systems. The greatest magnitude in COM vertical acceleration occurred at the slowest running pace and decreased as pace increased. Sixty percent of the athletes exhibited asymmetry during at least one running pace; 30% were asymmetrical across all three velocities. While significant changes in COM vertical acceleration occurred between the different running velocities, this did not always result in a change in symmetry. This study found that a single inertial sensor can be used as a valid means of measuring COM vertical acceleration. This technique can detect changes in the COM vertical acceleration that may change with running velocity. Gait symmetry (using COM vertical acceleration) during running was also quantified using the inertial sensor.

The use of a single inertial sensor to identify stride, step, and stance durations of running gait.

Current developments in inertial sensor technology could enable the measurement of running gait outside of the traditional laboratory environment. The purpose of this research was to determine the level of agreement between an inertial sensor and infrared camera based estimates of stride, step, and stance durations across a range of running speeds. An inertial sensor was placed on the sacrum of 10 elite national standard runners, and the stride, step, and stance of running gait were compared. A total of 504 samples were collected and the running velocities stratified into three equal groups of low (10-12 km/h), medium (13-15 km/h), and high (16-19 km/h). A single inertial sensor was found to be suitable for identifying stride duration with Bland-Altman limits of agreement of 95%. The stride data showed agreement at less than 0.02s for most limits. Agreement for step showed five of the eight upper and lower limits below 0.02s. The largest differences between both capture methods were for stance. An average bias of 0.0008s was found and standard error ranged between 0.0004s and 0.0009s across all variables. The results from this research found that inertial sensors are suitable to measure stride, step, and stance duration, and provide the opportunity to measure running gait outside of the traditional laboratory.