Isabel S. Moore

Mechanisms for Improved Running Economy in Beginner Runners.

UNLABELLED Controversy surrounds whether running mechanics make good predictors of running economy (RE) with little known about the development of an economical running gait. PURPOSE The aim of this study was to identify if mechanical or physiological variables changed during 10 wk of running in beginners and whether these changes could account for any change in RE. METHODS A 10-wk running program (10 wkRP) was completed by 10 female beginner runners. A bilateral three-dimensional kinematic and kinetic analysis, in addition to RE and lower body flexibility measurements, was performed before and after the 10 wkRP. The Balke-Ware graded walking exercise test was performed before and after the 10 wkRP to determine VO2max. RESULTS Seven kinematic and kinetic variables significantly changed from before to after training, in addition to a significant decrease in calf flexibility (27.3° ± 6.3° vs 23.9° ± 5.6°, P < 0.05). A significant improvement was seen in RE (224 ± 24 vs 205 ± 27 mL · kg(-1) · km(-1), P < 0.05) and treadmill time to exhaustion (16.4 ± 3.2 vs 17.3 ± 2.8 min, P < 0.05); however, VO2max remained unchanged from before to after training (34.7 ± 5.1 vs 34.3 ± 5.6 mL · kg(-1) · min(-1)). Stepwise regression analysis showed three kinematic variables to explain 94.3% of the variance in change in RE. They were a less extended knee at toe off (P = 0.004), peak dorsiflexion occurring later in stance (P = 0.001), and a slower eversion velocity at touchdown (P = 0.042). The magnitude of change for each variable was 1.5%, 4.7%, and 34.1%, respectively. CONCLUSIONS These results show that beginner runners naturally developed their running gait as they became more economical runners.

The pursuit of improved running performance: Can changes in cushioning and somatosensory feedback influence running economy and injury risk?

There is currently no consensus regarding the effect that barefoot (BFT) running has on running economy (RE). Stride length and shoe mass are confounding variables, with a BFT stride length being shorter than a shod (SH) stride length. Comparison of SH, minimalist shod (MS) and BFT allows controlled variation of cushioning and somatosensory feedback to determine the effect that either and/or both have on RE and running mechanics. Methods: Fifteen female habitually shod, recreational runners visited the laboratory twice. Familiarisation with BFT and SH treadmill running occurred during visit one, in addition to determining SH stride length and BFT stride length. During visit two participants ran BFT, SH and MS with BFT stride length and MS with SH stride length at 10 km·h−1 for six minutes with 10-minute rest periods between each condition. Lower limb kinematics, electromyography, impact acceleration and O2 were recorded during the final two minutes of each run. Results: BFT RE was significantly better than SH and MS with BFT stride length. SHRE was significantly worse than MS with SH stride length, but similar to MS with a BFT stride length. Low vertical oscillation, peak eversion and peak dorsiflexion, less plantarflexion at toe-off, in addition to an earlier occurrence of heel off, higher impact accelerations and greater tibialis anterior activity were observed during the most economical condition. Conclusions: Heightened somatosensory feedback and lack of cushioning (BFT) offered an advantage to economy over less somatosensory feedback (MS) and cushioning (SH). Whilst the low vertical oscillation and low plantarflexion at toe-off appear to contribute to the improved RE, other changes to running mechanics whilst BFT could potentially influence injury risk.

International consensus statement on injury surveillance in cricket: a 2016 update

Cricket was the first sport to publish recommended methods for injury surveillance in 2005. Since then, there have been changes to the nature of both cricket and injury surveillance. Researchers representing the major cricket playing nations met to propose changes to the previous recommendations, with an agreed voting block of 14. It was decided that 10 of 14 votes (70%) were required to add a new definition element and 11 of 14 (80%) were required to amend a previous definition. In addition to the previously agreed ‘Match time-loss’ injury, definitions of ‘General time-loss’, ‘Medical presentation’, ‘Player-reported’ and ‘Imaging-abnormality’ injuries are now provided. Further, new injury incidence units of match injuries per 1000 player days, and annual injuries per 100 players per year are recommended. There was a shift towards recommending a greater number of possible definitions, due to differing contexts and foci of cricket research (eg, professional vs amateur; injury surveillance systems vs specific injury category studies). It is recommended that researchers use and report as many of the definitions as possible to assist both comparisons between studies within cricket and with those from other sports.

Relationship between metabolic cost and muscular coactivation across running speeds

OBJECTIVES Muscular coactivation can help stabilise a joint, but contrasting results in previous gait studies highlight that it is not clear whether this is metabolically beneficial. The aim was to assess the relationship between the metabolic cost of running and muscular coactivation across different running speeds, in addition to assessing the reliability and precision of lower limb muscular coactivation. DESIGN Eleven female recreational runners visited the laboratory on two separate occasions. On both occasions subjects ran at three speeds (9.1, 11 and 12 km h(-1)) for six minutes each. METHODS Oxygen consumption and electromyographic data were simultaneously recorded during the final two minutes of each speed. Temporal coactivations of lower limb muscles during the stance phase were calculated. Five muscles were assessed: rectus femoris, vastus lateralis, biceps femoris, tibialis anterior and gastrocnemius lateralis. RESULTS Nonparametric correlations revealed at least one significant, positive association between lower limb muscular coactivation and the metabolic cost of running for each speed. The length of tibialis anterior activation and muscular coactivation of the biceps femoris-tibialis anterior and gastrocnemius lateralis-tibialis anterior decreased with speed. CONCLUSIONS These results show that longer coactivations of the proximal (rectus femoris-biceps femoris and vastus lateralis-biceps femoris) and leg extensor (rectus femoris-gastrocnemius lateralis) muscles were related to a greater metabolic cost of running, which could be detrimental to performance. The decrease in coactivation in the flexor and distal muscles at faster speeds occurs due to the shorter duration of tibialis anterior activation as speed increases, yet stability may be maintained.

“The Beast Within” Life With an Invisible Chronic Illness

This autoethnography documents the author’s lived experience while in the midst of an acute flare-up of ulcerative colitis (UC). Through depicting such a flare-up the depths of despair, anger, and frustration are relived. The disruption caused by the chronic illness upon daily functioning leads the author to reflect upon the influence of illness on an athletic body within a sporting subculture. Questions are raised regarding the “validity” of having an invisible chronic illness when confronted with what has been termed a “culture of risk.” The autoethnographical journey helps the author to understand issues of disclosure.

Injury Risk in International Rugby Union Three-Year Injury Surveillance of the Welsh National Team

Background: Within international Rugby Union, only injury rates during the Rugby World Cup have been reported. Therefore, injury rates and types during other international tournaments are unknown. Purpose: To assess the 3-year incidence, severity, nature, and causes of match and training injuries sustained during different international tournaments played by the Welsh national Rugby Union team. Study Design: Descriptive epidemiology study. Methods: Injury data for all players (n = 78) selected for 1 national Rugby Union team over a 3-year period were analyzed using the international consensus statement methods. Player height (cm) and mass (kg) were recorded. Tournaments were grouped for comparisons as: autumn tournaments (2012 and 2013), Rugby World Cup (RWC; 2011), Six Nations (2012, 2013, and 2014), and summer tournaments (2012, 2013, and 2014). Injury incidence (injuries/1000 hours), prevalence (% of players unavailable), and severity (days lost) were calculated for each tournament. Injury location, type, and cause of match and training injuries were analyzed. Results: Match injury incidence was highest during autumn tournaments (262.5/1000 match-hours) and lowest during the RWC (178.6/1000 match-hours). Summer tournaments had the highest training incidence (5.5 injuries/1000 training-hours). Mild injuries were most likely during the RWC (risk ratio [RR], 2.02; 95% CI, 1.26-3.24), while severe injuries were most likely during autumn tournaments (RR, 3.27; 95% CI, 1.70-6.29). Quadriceps hematomas (18.8/1000 match-hours; 95% CI, 11.3-31.1) and concussions (13.8/1000 match-hours; 95% CI, 7.6-24.8) were the most common match injuries, with shoulder dislocations being the most severe (111 mean days lost per injury). Conclusion: Injury rates were considerably higher than those previously reported for multiple teams during RWC tournaments. Further investigation of injury rates and risk factors is recommended to accurately gauge their impact within international Rugby Union, particularly with regard to lower limb hematoma, concussion, and shoulder injuries.

Effects of a seven-week minimalist footwear transition programme on footstrike modality, pressure variables and loading rates

Purpose: The aim was to compare footstrike modality and kinetics pre and post a seven week minimalist footwear transition programme. Methods: Ten recreational athletes (mass: 78.6 (8.7) kg, height: 179.4 (7.6) cm, age: 21.0 (0.7) years) performed overground running trials (3.8 m·s−1) whilst barefoot (BFT), minimal shod (MS) and shod (SH) both pre and post the programme. Ground reaction force and pressure data were simultaneously recorded for all footwear conditions. Footstrike modality was determined via visual inspection of the pressure distribution. Peak impact force, loading rate and peak regional pressures and impulses were compared pre and post, and between footwear conditions. The transition programme comprised of a two-week foot strengthening period followed by a five-week running transition. Results: Post transition there was a general trend for runners to adopt a more anterior footstrike in all three conditions. Additionally, loading rates and several peak pressures and impulses were found to decrease after the transition programme, with region specific changes evident for the effect of footwear. Furthermore, loading rates were higher whilst BFT and MS (instantaneous loading rates pre transition of 446.0 and 379.3 BW·s−1, respectively) compared to SH (105.8 BW·s−1). Conclusion: Whilst a seven-week MS transition programme was shown to decrease several kinetic variables, it was evident that both BFT and MS led to greater loading rates and peak pressures than SH running.

Reduced oxygen cost of running is related to alignment of the resultant GRF and leg axis vector: A pilot study

This pilot study investigated whether a 10‐week running program (10wkRP), which reduced the oxygen cost of running, affected resultant ground reaction force (GRF), leg axis alignment, joint moment characteristics, and gear ratios. Ten novice, female runners completed a 10wkRP. Running kinematics and kinetics, in addition to oxygen consumption ( V ˙ O 2 ) during steady‐state running, were recorded pre‐ and post‐10wkRP. V ˙ O 2 decreased (8%) from pre‐10wkRP to post‐10wkRP. There was a better alignment of the resultant GRF and leg axis at peak propulsion post‐10wkRP compared with pre‐10wkRP (10.8 ± 4.9 vs 1.6 ± 1.2°), as the resultant GRF vector was applied 7 ± 0.6° (P = 0.008) more horizontally. There were shorter external ankle moment arms (24%) and smaller knee extensor moments (23%) at peak braking post‐10wkRP. The change in V ˙ O 2 was associated with the change in alignment of the resultant GRF and leg axis (rs = 0.88, P = 0.003). As runners became more economical, they exhibited a more aligned resultant GRF vector and leg axis at peak propulsion. This appears to be a self‐optimization strategy that may improve performance. Additionally, changes to external ankle moment arms indicated beneficial low gear ratios were achieved at the time of peak braking force.

Changes in Sagittal Plane Kinematics With Treadmill Familiarization to Barefoot Running

Interest in barefoot running and research on barefoot running are growing. However a methodological issue surrounding investigations is how familiar the participants are with running barefoot. The aim of the study was to assess the amount of time required for habitually shod runners to become familiar with barefoot treadmill running. Twelve female recreational runners, who were experienced treadmill users, ran barefoot on a treadmill for three bouts, each bout consisting of 10 minutes at a self-selected speed with 5 minute rest periods. Sagittal plane kinematics of the hip, knee, ankle, and foot during stance were recorded during the first and last minute of each 10-minute bout. Strong reliability (ICC > .8) was shown in most variables after 20 minutes of running. In addition, there was a general trend for the smallest standard error of mean to occur during the same period. Furthermore, there were no significant differences in any of the biomechanical variables after 20 minutes of running. Together, this suggests that familiarization was achieved between 11 and 20 minutes of running barefoot on a treadmill. Familiarization was characterized by less plantar flexion and greater knee flexion at touchdown. These results indicate that adequate familiarization should be given in future studies before gait assessment of barefoot treadmill running.

Concussed or not? An assessment of concussion experience and knowledge within elite and semiprofessional rugby union

Objective:The primary aim was to assess experience and knowledge of adult concussion among international, professional and semiprofessional players, coaches, medical staff, and referees within Rugby Union. The secondary aim was to identify preferred education dissemination routes. Design:Questionnaires devised specifically for players, coaches, medical staff, and referees. Setting and Participants:A total of 370 players, 44 coaches, 40 medical staff, and 33 referees from within Wales were surveyed. Main Outcome Measures:Knowledge of the signs and symptoms of concussion, return to play guidelines and consequences of concussion were investigated along with experiences of, and attitudes towards, concussion. Results:The respondents had extensive experience of sustaining or witnessing rugby-related concussion. Medical staff had the greatest level of concussion knowledge, with coaches having the least. Players and coaches exhibited a disconnection between being “knocked-out” and practically applying this when managing concussion. Almost half of the players and coaches did not indicate concussion could impair performance. Eighty percent of medical staff had felt pressured to clear a concussed player. Most players (82%), coaches (66%), and referees (64%) incorrectly believed protective equipment prevents concussion. Players and coaches prefer concussion education from medical staff, whereas medical staff and referees prefer such education from governing body Web sites or training courses. Conclusions:Several role-specific misconceptions and deficiencies in concussion knowledge were identified and should be targeted through education. Medical staff had the highest level of concussion knowledge and were the preferred sources of education for players and coaches. Therefore, they are encouraged to play a greater role in providing concussion education.