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"Fletcher, Jared R."
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Increasing the midsole bending stiffness of shoes alters gastrocnemius medialis muscle function during running
2021
In recent years, increasing the midsole bending stiffness (MBS) of running shoes by embedding carbon fibre plates in the midsole resulted in many world records set during long-distance running competitions. Although several theories were introduced to unravel the mechanisms behind these performance benefits, no definitive explanation was provided so far. This study aimed to investigate how the function of the gastrocnemius medialis (GM) muscle and Achilles tendon is altered when running in shoes with increased MBS. Here, we provide the first direct evidence that the amount and velocity of GM muscle fascicle shortening is reduced when running with increased MBS. Compared to control, running in the stiffest condition at 90% of speed at lactate threshold resulted in less muscle fascicle shortening (
p
= 0.006,
d
= 0.87), slower average shortening velocity (
p
= 0.002,
d
= 0.93) and greater estimated Achilles tendon energy return (
p
≤ 0.001,
d
= 0.96), without a significant change in GM fascicle work (
p
= 0.335,
d
= 0.40) or GM energy cost (
p
= 0.569,
d
= 0.30). The findings of this study suggest that running in stiff shoes allows the ankle plantarflexor muscle–tendon unit to continue to operate on a more favourable position of the muscle’s force–length–velocity relationship by lowering muscle shortening velocity and increasing tendon energy return.
Journal Article
Identification of digital clinical decision support systems for supporting diagnosis and triage of patients with shoulder disorders: A scoping review protocol
by
Eubank, Breda H. F.
,
Schamerhorn, Cheyenne R.
,
Peñas, Nathaniel M.
in
Advisors
,
Algorithms
,
Artificial intelligence
2025
Clinical decision support systems (CDSSs) are computerized tools that support clinical decision-making processes. Primary care decision-making is complex and has the potential to influence quality of care provided and patient outcomes. CDSS not only assist providers with clinical decision-making to ensure quality standards are met, reflect evidence-informed practice, and reduce variation in care, but also help patients navigate and receive an appropriate care pathway amidst numerous, often complex, options. Therefore, this scoping review will aim to identify existing CDSSs for supporting primary point-of-care providers, directing patients to appropriate management pathways, and supporting the clinical examination (i.e., medical history-taking and physical examination) process for patients with shoulder disorders. At the primary point-of-care system level, a CDSS for shoulder disorders will improve clinical efficiency and support decision-making.
Scoping review methodology and reporting will be conducted according to Arksey and O'Malley's 6-step framework, the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocols (PRISMA-P), and the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) extension for Scoping Reviews (PRISMA-ScR) reporting guide. A robust search strategy will be applied across four databases: MEDLINE (Ovid), EMBASE (Ovid), CINAHL (Ebsco), and Scopus (Elsevier). Two blinded reviewers will independently evaluate all titles and corresponding abstracts based on pre-specified inclusion and exclusion criteria. Inter-rater reliability (IRR) agreement will be established during an initial pilot-screening phase against a random selection of 20 records (minimum) until reaching Cohen's Kappa ≥ 0.81. Data extraction will be completed by one reviewer and validated by a second.
An effective and high-quality CDSS that is affordable, easy to use, easily accessible, compatible with existing clinical processes, and generalizable across diverse settings will help to support primary point-of-care providers in diagnosing and managing patients presenting with shoulder disorders, thus improving quality of care for patients.
Journal Article
How Can Biomechanics Improve Physical Preparation and Performance in Paralympic Athletes? A Narrative Review
2021
Recent research in Paralympic biomechanics has offered opportunities for coaches, athletes, and sports practitioners to optimize training and performance, and recent systematic reviews have served to summarize the state of the evidence connecting biomechanics to Paralympic performance. This narrative review serves to provide a comprehensive and critical evaluation of the evidence related to biomechanics and Paralympic performance published since 2016. The main themes within this review focus on sport-specific body posture: the standing, sitting, and horizontal positions of current summer Paralympic sports. For standing sports, sprint and jump mechanics were assessed in athletes with cerebral palsy and in lower-limb amputee athletes using running-specific prostheses. Our findings suggest that running and jumping-specific prostheses should be ‘tuned’ to each athlete depending on specific event demands to optimize performance. Standing sports were also inclusive to athletes with visual impairments. Sitting sports comprise of athletes performing on a bike, in a wheelchair (WC), or in a boat. WC configuration is deemed an important consideration for injury prevention, mobility, and performance. Other sitting sports like hand-cycling, rowing, and canoeing/kayaking should focus on specific sitting positions (e.g., arm-crank position, grip, or seat configuration) and ways to reduce aero/hydrodynamic drag. Para-swimming practitioners should consider athlete-specific impairments, including asymmetrical anthropometrics, on the swim-start and free-swim velocities, with special considerations for drag factors. Taken together, we provide practitioners working in Paralympic sport with specific considerations on disability and event-specific training modalities and equipment configurations to optimize performance from a biomechanical perspective.
Journal Article
Is Running Power a Useful Metric? Quantifying Training Intensity and Aerobic Fitness Using Stryd Running Power Near the Maximal Lactate Steady State
by
Sales, Kate M.
,
van Rassel, Cody R.
,
Ajayi, Oluwatimilehin O.
in
critical intensity
,
Exercise intensity
,
Fitness equipment
2023
We sought to determine the utility of Stryd, a commercially available inertial measurement unit, to quantify running intensity and aerobic fitness. Fifteen (eight male, seven female) runners (age = 30.2 [4.3] years; V·O2max = 54.5 [6.5] ml·kg−1·min−1) performed moderate- and heavy-intensity step transitions, an incremental exercise test, and constant-speed running trials to establish the maximal lactate steady state (MLSS). Stryd running power stability, sensitivity, and reliability were evaluated near the MLSS. Stryd running power was also compared to running speed, V·O2, and metabolic power measures to estimate running mechanical efficiency (EFF) and to determine the efficacy of using Stryd to delineate exercise intensities, quantify aerobic fitness, and estimate running economy (RE). Stryd running power was strongly associated with V·O2 (R2 = 0.84; p < 0.001) and running speed at the MLSS (R2 = 0.91; p < 0.001). Stryd running power measures were strongly correlated with RE at the MLSS when combined with metabolic data (R2 = 0.79; p < 0.001) but not in isolation from the metabolic data (R2 = 0.08; p = 0.313). Measures of running EFF near the MLSS were not different across intensities (~21%; p > 0.05). In conclusion, although Stryd could not quantify RE in isolation, it provided a stable, sensitive, and reliable metric that can estimate aerobic fitness, delineate exercise intensities, and approximate the metabolic requirements of running near the MLSS.
Journal Article
Implementation strategies for hospital-based probiotic administration in a stepped-wedge cluster randomized trial design for preventing hospital-acquired Clostridioides difficile infection
2023
Background
Clostridioides difficile
infection (CDI) is associated with considerable morbidity and mortality in hospitalized patients, especially among older adults. Probiotics have been evaluated to prevent hospital-acquired (HA) CDI in patients who are receiving systemic antibiotics, but the implementation of timely probiotic administration remains a challenge. We evaluated methods for effective probiotic implementation across a large health region as part of a study to assess the real-world effectiveness of a probiotic to prevent HA-CDI (Prevent CDI-55 +).
Methods
We used a stepped-wedge cluster-randomized controlled trial across four acute-care adult hospitals (
n
= 2,490 beds) to implement the use of the probiotic Bio-K + ® (
Lactobacillus acidophilus
CL1285®,
L. casei
LBC80R® and
L. rhamnosus
CLR2®; Laval, Quebec, Canada) in patients 55 years and older receiving systemic antimicrobials. The multifaceted probiotic implementation strategy included electronic clinical decision support, local site champions, and both health care provider and patient educational interventions. Focus groups were conducted during study implementation to identify ongoing barriers and facilitators to probiotic implementation, guiding needed adaptations of the implementation strategy. Focus groups were thematically analyzed using the Theoretical Domains Framework and the Consolidated Framework of Implementation Research.
Results
A total of 340 education sessions with over 1,800 key partners and participants occurred before and during implementation in each of the four hospitals. Site champions were identified for each included hospital, and both electronic clinical decision support and printed educational resources were available to health care providers and patients. A total of 15 individuals participated in 2 focus group and 7 interviews. Key barriers identified from the focus groups resulted in adaptation of the electronic clinical decision support and the addition of nursing education related to probiotic administration. As a result of modifying implementation strategies for identified behaviour change barriers, probiotic adherence rates were from 66.7 to 75.8% at 72 h of starting antibiotic therapy across the four participating acute care hospitals.
Conclusions
Use of a barrier-targeted multifaceted approach, including electronic clinical decision support, education, focus groups to guide the adaptation of the implementation plan, and local site champions, resulted in a high probiotic adherence rate in the Prevent CDI-55 + study.
Journal Article
Changes in Achilles tendon stiffness and energy cost following a prolonged run in trained distance runners
by
MacIntosh, Brian R.
,
Fletcher, Jared R.
in
Achilles tendon
,
Achilles Tendon - physiology
,
Adult
2018
During prolonged running, the magnitude of Achilles tendon (AT) length change may increase, resulting in increased tendon strain energy return with each step. AT elongation might also affect the magnitude of triceps surae (TS) muscle shortening and shortening velocity, requiring greater activation and increased muscle energy cost. Therefore, we aimed to quantify the tendon strain energy return and muscle energy cost necessary to allow energy storage to occur prior to and following prolonged running. 14 trained male (n = 10) and female (n = 4) distance runners (24±4 years, 1.72±0.09 m, 61±10 kg, [Formula: see text] 64.6±5.8 ml•kg-1•min-1) ran 90 minutes (RUN) at approximately 85% of lactate threshold speed (sLT). Prior to and following RUN, AT stiffness and running energy cost (Erun) at 85% sLT were determined. AT energy return was calculated from AT stiffness, measured with dynamometry and ultrasound and estimated TS force during stance. TS energy cost was estimated on the basis of AT force and assumed crossbridge mechanics and energetics. Following RUN, AT stiffness was reduced from 328±172 N•mm-1 to 299±148 N•mm-1 (p = 0.022). Erun increased from 4.56±0.32 J•kg-1•m-1 to 4.62±0.32 J•kg-1•m-1 (p = 0.049). Estimated AT energy return was not different following RUN (p = 0.99). Estimated TS muscle energy cost increased significantly by 11.8±12.3 J•stride-1, (p = 0.0034), accounting for much of the post-RUN increase in Erun (8.6±14.5 J•stride-1,r2 = 0.31). These results demonstrate that a prolonged, submaximal run can reduce AT stiffness and increase Erun in trained runners, and that the elevated TS energy cost contributes substantially to the elevated Erun.
Journal Article
Can muscle shortening alone, explain the energy cost of muscle contraction in vivo?
by
Pfister, Ted R.
,
MacIntosh, Brian R.
,
Groves, Erik M.
in
Achilles Tendon - physiology
,
Adult
,
Biomedical and Life Sciences
2013
Purpose
Decreased whole-body energy cost of running has been associated with an increased Achilles tendon stiffness. It is usually assumed that this lower energy cost can be attributed to less muscle fascicle shortening with a stiffer tendon. Increased fiber shortening is an important determinant of muscle energetics in vitro. However, other factors, like increased muscle activation may be important when considering whole muscle energetics in vivo.
Methods
To determine the effects of a small additional muscle shortening on skeletal muscle energy requirement, 19 subjects performed 30 plantarflexions on two separate occasions: isometric (ISO) and isokinetic (KIN, 6.98 rad s
–1
), each with a target of 50 % of maximum isometric torque. Medial gastrocnemius muscle fascicle length (FL) was measured by ultrasound and rate of oxyhemoglobin (HbO
2
) desaturation was measured during blood flow occlusion using near-infrared spectroscopy.
Results
KIN resulted in significantly greater muscle shortening (23.8 ± 1.3 mm) than ISO (18.3 ± 1.0 mm,
p
< 0.001, mean ± SEM), and greater shortening velocity (KIN = 2.5 ± 0.3 FL s
–1
, ISO = 1.1 ± 0.1 FL s
–1
,
p
< 0.001). Rate of HbO
2
desaturation was 19 ± 7 %, greater in KIN than ISO (
p
< 0.01), despite 19 ± 2 % lower mean torque (
p
< 0.001) and 9.8 ± 1.6 Nm s lower mean impulse per contraction (
p
< 0.001) in KIN compared to ISO. Root mean square for EMG was significantly greater (
p
< 0.05) during KIN (73 ± 3 %) than during ISO (63 ± 2 %).
Conclusion
These results illustrate that muscle energy requirement is greater when muscle fascicle shortening and/or velocity of shortening is increased, and suggest that greater activation contributes to that increased energy requirement.
Journal Article
Mechanisms of reduced plantarflexor function in Cerebral palsy: smaller triceps surae moment arm and reduced muscle force
by
Gallinger, Tessa L.
,
MacIntosh, Brian R.
,
Fletcher, Jared R.
in
Achilles Tendon - diagnostic imaging
,
Angular velocity
,
Ankle
2020
Both muscle forces, and moment arm (MA) could contribute to reduced muscle moment in people with Cerebral Palsy (CP). Current reports in CP are conflicting. The tendon travel method of estimating MA requires constant force, but passive force is high and variable in CP, and range of motion is limited. Therefore, the purpose of this study was to examine triceps surae muscle MA in 12 subjects with mild to moderate CP (15–32 years) and 10 typically developing peers (TD, 17–26 years) by tendon travel and by visually measuring the apparent MA. MA was calculated at 90° and at a reference angle (∼106°) with zero net passive moment. The tendon travel (28.8 ± 5.6 mm) and visual methods (29.1 ± 5.5 mm) yielded similar MA in CP (p = 0.94) at the reference angle. TD had significantly larger triceps surae muscle MA than CP subjects (p = 0.002), 35.4 ± 4.1 mm at the reference angle for tendon travel and 35.4 ± 3.6 mm by the visual method. Test/retest revealed less bias (0.8 mm) using the visual method. Calculated active peak isometric force was significantly less in CP (1983.8 ± 887.0 N) than TD (4104.9 ± 1154.9 N, p < 0.001). There are challenges in estimating MA in CP, but the visual method is more reliable. Although a shorter moment arm would reduce the joint moment, joint angular velocity for a given velocity of muscle shortening would be enhanced. Strength training may mitigate the effects of the smaller moment arm and reduced joint moment generated in those with CP.
Journal Article
Theoretical considerations for muscle-energy savings during distance running
2018
We have recently demonstrated that the triceps surae muscles energy cost (ECTS) represents a substantial portion of the total metabolic cost of running (Erun). Therefore, it seems relevant to evaluate the factors which dictate ECTS, namely the amount and velocity of shortening, since it is likely these factors will dictate Erun. Erun and triceps surae morphological and AT mechanical properties were obtained in 46 trained and elite male and female distance runners using ultrasonography and dynamometry. ECTS (J·stride−1) at the speed of lactate threshold (sLT) was estimated from AT force and crossbridge mechanics and energetics. To estimate the relative impact of these factors on ECTS, mean values for running speed, body mass, resting fascicle length (Lf), Achilles tendon stiffness and moment arm and maximum isometric plantarflexion torque were obtained. ECTS was calculated across a range (mean ± 1 sd) of values for each independent factor. Average sLT was 233 m·min−1. At this speed, ECTS was 255 J·stride−1. Estimated fascicle shortening velocity was 0.08 Vmax and the level of muscle activation was 84.7% of maximum isometric torque. Compared to the ECTS calculated from the lowest range of values obtained for each independent factor, higher AT stiffness was associated with a 39% reduction in ECTS, 81% reduction in fascicle shortening velocity and a 31% reduction in muscle activation. Longer AT moment arms and elevated body masses were associated with an increase in ECTS of 18% and 23%, respectively. These results demonstrate that a low ECTS is achieved primarily from a high AT stiffness and low body mass, which is exemplified in elite distance runners.
Journal Article
Changes in tendon stiffness and running economy in highly trained distance runners
by
MacIntosh, Brian R.
,
Esau, Shane P.
,
Fletcher, Jared R.
in
Biological and medical sciences
,
Fundamental and applied biological sciences. Psychology
,
Vertebrates: body movement. Posture. Locomotion. Flight. Swimming. Physical exercise. Rest. Sports
2010
Journal Article