A New Look at Vertebral Body Tethering (VBT): Through the Modified Clavien-Dindo-Sink (mCDS) Classification.

INTRODUCTION: Anterior vertebral body tethering (AVBT) is increasingly popular as an option for surgical treatment of idiopathic scoliosis (IS). While the technology remains new, it is important for families and patients to be able to compare it to the current standard of care, posterior spinal fusion (PSF). The purpose of this study is to describe the complication rate of AVBT in IS using the mCDS and to compare it to the recently reported complication rate of PSF in IS. METHODS: A multicenter pediatric spine deformity database was queried for all idiopathic scoliosis patients who underwent vertebral body tethering. There were 171 patients with a minimum 9-month follow-up included in this study. Complications were retrospectively graded by 2 attending pediatric spine surgeons using the mCDS classification system. RESULTS: Data from 171 patients with idiopathic scoliosis was available for analysis, with 156/171 (91%) of patients being female and an average age of 12.2 years old at surgery. There were 156 thoracic tethers (1 with an LIV below L2), 5 lumbar tethers, 9 staged double tethers, and only 1 patient with same-day double tether. Fifty-five (55) (32%) patients experienced a total of 69 complications. The most common complication type for VBT by mCDS was Grade IIIb, encompassing 29/69 (42%) of complications. The second most frequent complication grade was Grade I at 23/69 (33%). Thirty-four (34) out of 69 (49%) of the VBT complications reported required either procedural/surgical intervention or admission to the ICU. CONCLUSIONS: This is the first study to directly compare the complication profile of VBT to PSF using the mCDS. Forty-nine percent (49%) of the VBT complications reported were at least Grade III, while only 7% of complications in the control PSF cohort from the literature were Grade III or higher. The mCDS complication classification brings light to the early learning experience of a new technique compared to the widely accepted standard of PSF for IS. LEVEL OF EVIDENCE: III - Retrospective comparative study.

Effect of goalkeepers' offensive participation on team performance in the women Spanish La Liga: a multinomial logistic regression analysis.

This study aimed to examine the effect of goalkeeper distribution on offensive team performance, during the 2018/2019 and 2019-2020 seasons of the Women Spanish La Liga. A total of 10,868 distributions, during 376 matches were analyzed by systematic observation. Two UEFA PRO coaches designed an ad hoc observation instrument "GOALDFOOT" and one observer coded the data after a training process. An intra-observer reliability kappa index of 0.94 was established. Results show how the offensive effectiveness of the goalkeepers was similar to outfield players, with 0.4% of possessions ending in a goal, 2.2% ending in an attempt on goal, with 79.4% ending unsuccessfully. The goalkeeper lost possession from their distribution 32.5% of the time. Multivariate analysis identified several predictors of goalkeepers' distributions. The results show that teams classified in the middle zone of the final classification of the regular league had 1.2 times more probability of being successful compared with the lowest ranked teams (p < 0.05). Goalkeeper's distribution beginning during Open play after a transition, represented an increase success rate of almost 3 times compared to being performed from a free kick (p < 0.05). Passes from outfield players to a goalkeeper made from distant zones to the own goal, decreased the probability of success (p < 0.001). The pitch location of the distribution outcome near to the opponent goal offered the best probability of success. In conclusion, the most effective offensive sequences occur with dynamic transitions initiated with short passes. This information can provide coaches and players with insights to improve the offensive performance of goalkeepers.

Feasibility of Parkour-style training in team sport practice: A Delphi study.

Research has suggested Parkour-style training could act as a donor sport for athlete development in team sports. This study aimed to interrogate expert consensus on the feasibility of integrating Parkour-style training into team sport practice, by employing a three-round, online Delphi method. Talent development and strength and conditioning coaches working in team sport settings were invited to participate. Twenty-four coaches completed Round One, 21 completed Round Two and 20 completed Round Three. In Round One, coaches answered 15 open-ended questions across four categories: (1) General Perceptions of Parkour-style training; (2) Potential Applications of Parkour-style training; (3) Designing and Implementing Parkour-style training Environments; and (4), Creating an Inclusive Learning Environment. Responses from Round One were analysed using reflexive thematic analysis with deductive and inductive coding resulting in 78 statements across three dimensions (Application of Parkour Style Training in Team Sports; Designing and Implementing Parkour-style training Environments; Overcoming Potential Barriers when Integrating Parkour-style training). In Rounds Two and Three, coaches rated these statements using a four-point Likert scale and measures of collective agreement or disagreement were calculated. This study established consensus around a set of design principles for integrating Parkour-style training into team sport practice routines.

When Is a Growth-friendly Strategy Warranted? A Matched Comparison of Growing Rods Versus Primary Posterior Spinal Fusion in Juveniles With Early-onset Scoliosis.

BACKGROUND: In 7 to 11-year-old juveniles with severe early-onset scoliosis (EOS) the optimal surgical option remains uncertain. This study compares growing rods (GRs) followed by definitive posterior spinal fusion (PSF) versus primary PSF in this population. We hypothesized that the thoracic height afforded by GRs would be offset by increased rigidity, more complications, and more operations. METHODS: This retrospective comparative study included EOS patients aged 7.0 to 11.9 years at index surgery treated with GR→PSF or primary PSF during 2013 to 2020. Primary outcomes were thoracic height gain (ΔT1-12H), major curve, complications, and total operations. Primary PSFs were matched with replacement 1-to-n to GR→PSFs by age at index, etiology, and major curve. RESULTS: Twenty-eight GR→PSFs met criteria: 19 magnetically controlled GRs and 9 traditional GRs. Three magnetically controlled GRs were definitively explanted without PSF due to complications. The remaining 25 GR→PSFs were matched to 17 primary PSFs with 100% etiology match, mean Δ major curve 1 degree, and mean Δ age at index 0.5 years (PSFs older). Median ΔT1-12H pre-GR to post-PSF was 4.7 cm with median deformity correction of 37%. Median ΔT1-12H among primary PSFs was 1.9 cm with median deformity correction of 62%. GR→PSFs had mean 1.8 complications and 3.4 operations. Primary PSFs had mean 0.5 complications and 1.3 operations. Matched analysis showed adjusted mean differences of 2.3 cm greater ΔT1-12H among GR→PSFs than their matched primary PSFs, with 25% less overall coronal deformity correction, 1.2 additional complications, and 2.2 additional operations per patient. CONCLUSIONS: In juveniles aged 7 to 11 with EOS, on average GRs afford 2 cm of thoracic height over primary PSF at the cost of poorer deformity correction and additional complications and operations. Primary PSF affords an average of 2 cm of thoracic height gain; if an additional 2 cm will be impactful then GRs should be considered. However, in most juveniles the height gained may not warrant the iatrogenic stiffness, complications, and additional operations. Surgeons and families should weigh these benefits and harms when choosing a treatment plan. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Kinematic modifications of the lower limb during the acceleration phase of bend sprinting.

A decrease in speed when sprinting on the bend compared with the straight has been attributed to kinetic, kinematic and spatiotemporal modifications. Although maximal speed is dependent on an athlete's ability to accelerate, there is limited research investigating the acceleration phase of bend sprinting. This study used a lower limb and trunk marker set with 15 optoelectronic cameras to examine kinematic and spatiotemporal variables of the lower limb during sprinting on the bend and straight. Nine sprinters completed up to six 30 m maximal effort trials in bend (radius 36.5 m, lane one) and straight conditions. An increase in body lateral lean at touchdown resulted in a number of asymmetric kinematic modifications. Whilst the left limb demonstrated a greater peak hip adduction, peak hip internal rotation and peak ankle eversion on the bend compared with the straight, the right limb was characterised by an increase in peak hip abduction. These results demonstrate that kinematic modifications start early in the race and likely accumulate, resulting in greater modifications at maximal speed. It is recommended that strength and conditioning programmes target the hip, ankle and foot in the non-sagittal planes. In addition, sprint training should prioritise specificity by occurring on the bend.

Horizontal force production and multi-segment foot kinematics during the acceleration phase of bend sprinting.

This paper investigated horizontal force production, foot kinematics, and metatarsophalangeal (MTP) joint push-off axis use during acceleration in bend (anti-clockwise) and straight-line sprinting. It was hypothesized that bend sprinting would cause the left step push-off to occur about the oblique axis, resulting in a decrease in propulsive force. Three-dimensional kinematic and ground reaction force data were collected from nine participants during sprinting on the bend (36.5 m radius) and straight. Antero-posterior force was reduced at 38%-44% of stance during bend sprinting compared with the straight. This coincided with an increase in mediolateral force for the majority of the stance phase (3%-96%) on the bend compared with the straight. In addition, a lower propulsive impulse was reported on the bend compared with the straight. Analysis of multi-segment foot kinematics provides insight into the possible mechanisms behind these changes in force production. Mean mediolateral center of pressure position was more lateral in relation to the second metatarsal head in the left step on the bend compared with the straight, indicating the oblique axis was used for push-off at the MTP joint. Greater peak joint angles of the left foot were also reported, in particular, an increase in left step midfoot eversion and internal ankle rotation. It is possible these changes in joint kinematics are associated with the observed decrease in propulsive force. Therefore, practitioners should seek to strengthen muscles such as tibialis posterior in frontal and sagittal planes and ensure specificity of training which may aid in addressing these force reductions.

Effects of Lawn Tennis Association mini tennis as task constraints on children's match-play characteristics.

The Lawn Tennis Association's mini tennis (MT) is a modified version of tennis consisting of progressive stages; however, there have been few attempts to evaluate how MT might shape performance behaviours. Here, we examine effects of playing MT on the emergence of children's match-play behaviours in 48 junior tennis players. Performance in 1010 match-play points were filmed and coded across 4 tennis stages (MT Red, MT Orange, MT Green and Full Ball), using a notational analysis system. Recorded performance variables included rally length, first serve percentage and shot type, for the purpose of analysing inter-stage comparisons. Results showed a series of specific adaptations to playing characteristics across the stages, including rally length, shot variety and serve success. MT Red rallies (7.36 ± 6.06) were longer than Full Ball rallies (3.83 ± 2.40), and a higher percentage of forehands were played at MT Red (66.40 ± 8.49%) than at Full Ball stage (45.96 ± 6.47%). Findings suggested that MT stages can afford children more opportunities to develop their skills and elicit different match-play characteristics than Full Ball task constraints. Coaches, therefore, should consider the nature of emergent adaptations when designing practice environments to facilitate learning in young tennis players.

The Use of a Transolecranon Pin in the Treatment of Pediatric Flexion-type Supracondylar Humerus Fractures.

BACKGROUND: Flexion-type supracondylar humerus fractures are much more uncommon than their extension-type counterparts. Instability in elbow flexion renders traditional closed techniques inadequate and often results in the need for open reduction. We present a simple technique for closed reduction using a transolecranon pin for temporary stability. METHODS: A retrospective review of 9 patients treated with a transolecranon pin technique for a flexion-type supracondylar humerus fracture was performed. Operative time, need for open reduction, postoperative range of motion, final radiographic alignment using Baumann angle, and the intersection of the anterior humeral line with the capitellum was evaluated. RESULTS: All 9 patients were treated with closed reduction using a temporary transolecranon pin technique. Total surgical time averaged 38±15 minutes and was longer for type III than type II flexion-type fractures. All fractures healed by first follow-up at 1 month. There was 1 preoperative ulnar nerve deficit that resolved by the first postoperative visit. Average Baumann angle at radiographic healing was 71.2±3.3 degrees and all cases showed restoration of the normal anterior humeral line:capitellar relationship. Average postoperative flexion at final follow-up was 125 degrees and extension was 5 degrees. One patient had a flexion contracture of 10 degrees. DISCUSSION: Use of a temporary transolecranon pin allowed for closed reduction of all flexion-type fractures with no radiographic malunion. This technique is technically simple and avoids the need for open reduction or multiple fluoroscopy views. LEVEL OF EVIDENCE: Level IV-case series.

Emergent perception-action couplings regulate postural adjustments during performance of externally-timed dynamic interceptive actions.

Studies of postural coordination during performance of externally-timed interceptive actions, such as catching a ball, have been infrequent, with advanced visual information from a thrower's actions towards a catcher, typically excluded in experimental task constraints. Yet previous research suggests that manipulating participant access to such information alters their hand movements and gaze behaviours when catching. In this study, we manipulated participant access to advanced information of a thrower's actions, and from ball flight, while recording whole body kinematic and kinetic data to investigate effects on postural control during performance of interceptive actions. Twelve participants attempted to make or simulate performance of one-handed catches in three experimental conditions: when facing integrated videos of advanced visual information and ball flight only, videos of a thrower's actions only, and of ball flight only. Findings revealed when integrating advanced visual information and ball flight, and when participants were provided with ball flight information only, lower limb adjustments were primarily used to regulate posture. However, movement was initiated earlier when advanced visual information was available prior to ball flight, resulting in more controlled action and superior catching performance in the integrated condition. When advanced visual information was presented without ball flight, smaller displacements were observed in lower limb joint angles, resulting in upward projection of the centre of mass, compared to a downward trajectory when ball flight information was available, in the integrated video and ball flight, and ball-flight only conditions. Results revealed how postural coordination behaviors are dependent on specific informational constraints designed into experiments, implying that integration of task constraints in studies of human perception and action needs careful consideration.

Using video docuseries to explore male professional football head coaches' well-being experiences throughout a season.

Football coaches have disclosed how their work environment is unpredictable and demanding, comprising a multitude of stressors which can impede well-being. Additionally, the masculine culture within football often promotes suppression of voice, causing internalisation of thoughts and isolation. Due to professional football head coaches being a seldom-heard group, little is known about how they experience well-being within their given context (i.e., ecological niche). The present study utilised football docuseries and a bioecological framework to explore how four male professional head coaches experienced well-being whilst working in one of the top European football leagues (Premier League, La Liga). Four docuseries were sampled and resulted in the analysis of 31 episodes (Mduration = 46.6 min, SD = 4.5 min). The study implemented an adapted interpretative phenomenological analysis approach to illuminate convergences and divergences in contextual accounts. These accounts resulted in five group experiential themes: 'I belong to the game'; 'he belongs to the game'; 'you need the right people around you'; 'it's difficult to describe the manager without describing the person'; and 'people are trying to stab you'. The findings indicate that football coaches may experience identity conflicts and become deeply absorbed in their work. This impacts not only their well-being but also their family's, who they often turn to for social support. Consequently, by unveiling nuanced challenges to coaches' well-being, organisations may be better informed to offer more aligned and bespoke well-being support systems.

Effects of functional movement skills on parkour speed-run performance.

Parkour speed-runs require performers (known as Traceurs) to negotiate obstacles with divergent properties such as angles, inclinations, sizes, surfaces, and textures in the quickest way possible. The quicker the run, the higher the performer is ranked. Performance in Parkour speed-runs may be regulated through Parkour Traceurs' functional movement skill capacities given the physical requirements of the event. This study examined what functional movement skills correlate with Parkour speed-run performance. Nineteen male Parkour Traceurs undertook a physical testing battery inclusive of: agility T-test, maximal grip strength test, and maximal vertical and horizontal jumps across several jump modalities. For the speed-run, Parkour Traceurs navigated an indoor Parkour installation. Pearson's correlation analyses (r) revealed that agility T-test performance showed a significant positive correlation with Parkour speed-run performance, whereas standing long jump and counter movement jump (with and without arm swing) were significantly negatively correlated with Parkour speed-run performance. Concurrent with the intrinsically-linked building blocks in the Athletic Skills Model, the data from the present study suggest that performance in Parkour-speed-runs are underpinned by functional movement skills (jumping, running; arm swinging) and conditions of movement (agility), all of which encapsulate elements of basic motor properties (speed; strength). From a practical perspective, the agility T-test, standing long jump, and counter movement jump with and without arm swing can form a basic battery to evaluate the physical effects of Parkour speed-run interventions on functional movement skills. HighlightsAs Parkour speed-runs could be implemented to improve functional movement skills in different domains (indoors, outdoors, collectively as members of a team or individually), it was important to explore what composition of a battery of standardised athletic tests for functional movement skills correlated to Parkour speed-run performance (time to completion).In line with the intrinsically-linked building blocks in the Athletic Skills Model, the data from the present study suggest that performance in Parkour-speed-runs are underpinned by functional movement skills (jumping, running; arm swinging) and condition of movement (agility), all of which encapsulate elements of basic motor properties (speed; strength).Testing batteries examining the effects of Parkour speed-run interventions should include the following: agility T-test, CMJ jumps without arm swing using both feet and the dominant and the non-dominant foot, SLJ, and CMJ jumps with an arm swing component using both feet and the dominant and the non-dominant foot.

Complications following posterior spinal fusion for adolescent idiopathic scoliosis: a retrospective cohort study using the modified Clavien-Dindo-Sink system.

PURPOSE: Published complication rates after posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) range from 1 to 22%. Complications are often minor and may be underestimated in registries. This study describes complications of PSF for AIS, classifies them according to a Clavien-Dindo-Sink (CDS) system, and investigates risk factors for occurrence of a complication. METHODS: This retrospective cohort study at two academic centers included all AIS patients aged 10-18 who underwent primary PSF 4/2014-12/2019. Data included demographics, comorbidities, curve magnitude, Lenke classification, levels osteotomized/fused, implant density, 90-day emergency department visits, readmissions, reoperations, and complications as defined by Harms Study Group. RESULTS: Among 424 patients, mean age was 14.7, mean BMI 22, 77% were female, and 57% had no comorbidities. There were 270 complications (0.64 per patient); 198 patients (47%) had ≥ 1 complication; and 63 patients (15%) had CDS grade ≥ II complications (deviation from standard postoperative course). Complications not related to persistent pain occurred in 103 patients (24%). Ninety-three percent of complications did not require readmission or reoperation (CDS I-II). Within 90 days, 8% presented to an ED, 2% required readmission, and 2% required reoperation. Common complications were back pain > 6 weeks postoperatively (26%), surgical site complications (7%), and ileus/prolonged constipation (3%). Risk factors for experiencing any complication were BMI ≥ 34 (OR 3.44) and Lenke 6 curve (OR 1.95). CONCLUSION: One in four AIS patients experiences a complication not related to persistent pain after primary PSF, higher than rates published from self-reported registries. Obesity and Lenke 6 curve may increase risk. While most do not require readmission or surgery, 15% of patients have their postoperative course altered by complications. LEVEL OF EVIDENCE: III-retrospective cohort study.

Modified Clavien-Dindo-sink classification system for adolescent idiopathic scoliosis.

PURPOSE: The Clavien-Dindosink (CDS) classification system provides more treatment-focused granularity than subjective methods of describing surgical complications; however, it has not been validated in posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS). The purpose of this study was to modify the CDS system for application in patients with AIS undergoing PSF to assess its inter- and intra-rater reliability for describing complications faced by this population. METHODS: A review of all complications specific to patients with AIS captured in a large multicenter international database was performed. All complications were classified according to CDS, modified by addition of "prolonged initial hospital stay" as a criterion for Grade II. A survey of this complication list and an additional 20 clinical vignettes (sent out on two occasions) was sent to nine spinal deformity surgeons. Weighted kappa values were used to determine inter- and intra-rater reliability. RESULTS: The Fleiss κ value for interrater reliability among 5 respondents grading all AIS complications was 0.8 (very good). For each grade, interrater reliability was very good, with an overall range of 0.8-1. The overall kappa value for intrarater reliability among eight respondents grading 20 vignettes was between 0.6 (good) and 0.9 (very good). CONCLUSION: The modified CDS classification system has very good interrater and intrarater reliability in describing complications following PSF in patients with AIS. This system may be of greater utility for reporting outcomes than a "major" versus "minor" complication system and can serve as a valuable tool for improving surgical practices and patient outcomes in this population. LEVEL OF EVIDENCE: IV case series.

Exome sequencing of individuals with Huntington's disease implicates FAN1 nuclease activity in slowing CAG expansion and disease onset.

The age at onset of motor symptoms in Huntington's disease (HD) is driven by HTT CAG repeat length but modified by other genes. In this study, we used exome sequencing of 683 patients with HD with extremes of onset or phenotype relative to CAG length to identify rare variants associated with clinical effect. We discovered damaging coding variants in candidate modifier genes identified in previous genome-wide association studies associated with altered HD onset or severity. Variants in FAN1 clustered in its DNA-binding and nuclease domains and were associated predominantly with earlier-onset HD. Nuclease activities of purified variants in vitro correlated with residual age at motor onset of HD. Mutating endogenous FAN1 to a nuclease-inactive form in an induced pluripotent stem cell model of HD led to rates of CAG expansion similar to those observed with complete FAN1 knockout. Together, these data implicate FAN1 nuclease activity in slowing somatic repeat expansion and hence onset of HD.

Parkour-Based Activities in the Athletic Development of Youth Basketball Players.

While ideas from long-term athlete development (LTAD) models have been adopted and integrated across different sports, issues related to early specialization, such as increased risk of injury and burnout, are still common. Although some benefits may be associated with early sport specialization, sports sampling is purported to be a more effective approach to the long-term health and wellbeing of children. Furthermore, the concept of developing what are commonly referred to as "fundamental movement skills" (FMS) is central to the rationale for delaying single sports specialization. However, in place of sports sampling, it appears that the practice of strength and conditioning (S&C) has become a driving force behind developmental models for youth athletes, highlighted by the growing body of literature regarding youth athletic development training. In this perspective piece, we explore how conventional S&C practice may insufficiently develop FMS because typically, it only emphasizes a narrow range of foundational exercises that serve a limited role toward the development of action capabilities in youth athletic populations. We further discuss how this approach may limit the transferability of physical qualities, such as muscular strength, to sports-specific tasks. Through an ecological dynamics lens, and using basketball as an example, we explore the potential for parkour-based activity within the LTAD of youth basketball players. We propose parkour as a training modality to not only encourage movement diversity and adaptability, but also as part of an advanced strength training strategy for the transfer of conventional S&C training.

Power versus manual pedicle tract preparation: a multi-center study of early adopters.

STUDY DESIGN: Retrospective cohort, multicenter. A single surgeon study demonstrated that pedicle tract preparation with power tools was associated with lower fluoroscopy times and revision rates compared to manual tools, while maintaining patient safety. OBJECTIVE: Our purpose was to determine the safety of power-assisted pedicle tract preparation by early adopters of this technology. METHODS: Retrospective review comparing patients that underwent posterior spinal fusion by seven pediatric spine surgeons at six institutions between January 1, 2008 and August 31, 2019. The manual pedicle tract preparation used a pedicle awl. Power tract preparation used a flexible 2.0-2.4 mm drill bit, followed by a larger drill bit or a reamer. All screws were inserted with power technique. RESULTS: In the manual tract preparation group, 9424 screws were placed in 585 cases. In the power tract preparation group, 22,209 screws were placed in 1367 cases. Seven patients (7/1952; 0.36%; 95% CI: 0.14-0.74%) had 11 mal-positioned screws (11/31,633; 0.03%; 95% CI: 0.017-0.062%). Seven screws (7/9424; 0.07%; 95% CI: 0.030-0.15%) were in the manual cohort and four (4/22,209; 0.02%; 95% CI: 0.0049-0.046%) were in the power cohort. There were significantly more revisions per screw in the manual cohort (p = 0.02). However, there were not significantly more revisions per patient in the manual cohort (manual: 0.5%, 3/585 vs. power: 0.3%, 4/1,367; p = 0.43). Of these seven, three patients (3/585; 0.5%; 95% CI: 0.1-1.5%) experienced neurologic injury or neuro-monitoring changes requiring screw removal in the manual cohort, and 1 patient (1/1,367, 0.07%; 95% CI: 0.002-0.4%) in the power cohort (p = 0.08). Three additional patients underwent revision in the power cohort: 1 for an asymptomatic lateral breech, 1 for a spinal headache/medial breech that developed after an MVA, and 1 for an iliac vein injury during pedicle tract preparation. CONCLUSION: This is the first multi-center study examining power pedicle preparation. Overall, 99.9% of pedicle screws placed with power pedicle preparation did not have complications or revision. Equivalent patient safety was demonstrated compared to manual technique. LEVEL OF EVIDENCE: III.

Joint moments and power in the acceleration phase of bend sprinting.

Joint kinetics of the lower limb (hip, knee, ankle, midfoot and metatarsophalangeal joints) were investigated during the acceleration phase of bend sprinting and straight-line sprinting. Within the bend sprinting literature, it is generally accepted that sprint performance on the bend is restricted by moments in the non-sagittal plane preventing the production of force in the sagittal plane. However, there is limited evidence in conditions representative of elite athletics performance that supports this hypothesis. Three-dimensional kinematic and ground reaction force data were collected from seven participants during sprinting on the bend (36.5 m radius) and straight, allowing calculation of joint moment, power and energy. No changes in extensor moment were observed at the hip and knee joints. Large effect sizes (g = 1.07) suggest a trend towards an increase in left step peak ankle plantarflexion moment. This could be due to a greater need for stabilisation of the ankle joint as a consequence of non-sagittal plane adaptations of the lower limb. In addition, the observed increase in peak MTP joint plantar-flexor moment might have implications for injury risk of the fifth metatarsal. Energy generation, indicated by positive power, in the sagittal plane at the MTP and ankle joints was moderately lower on the bend than straight, whilst increases in non-sagittal plane energy absorption were observed at the ankle joint. Therefore, energy absorption at the foot and ankle may be a key consideration in improving bend sprinting performance.

Measurement of bend sprinting kinematics with three-dimensional motion capture: a test-retest reliability study.

Sprint velocity decreases on the bend when compared with the straight, therefore understanding technique during bend sprinting could have important implications for aiding race performance. Few bend sprinting studies have used optoelectronic cameras to investigate kinematic variables. Limited published evidence regarding the reliability of marker sets in conditions representative of elite bend sprinting makes model selection difficult. Therefore, a test-retest protocol was conducted to establish the reliability and minimum detectable difference of a lower limb and trunk marker set during bend sprinting (radius: 36.5 m). Six participants completed five, 60 m trials at maximum effort, with data collected at 38-45 m. This was repeated 2-7 days later. Spatio-temporal (e.g., contact time) and kinematic variables (e.g., peak joint angles) were evaluated. Intra-class correlation coefficients (ICC) were used to determine the between- and within-day reliability. Between-day reliability (ICC 3, k) was fair to excellent for all variables. Compared to between-day, within-day reliability demonstrated stronger agreement for the majority of variables. Thus, same-day data collection is preferable. It has been established that the marker set is reliable for future use. In addition, the minimal detectable difference was calculated which serves as useful reference for future research in bend sprinting.

Reflections on a proposed theory of reservation-dwelling American Indian alcohol use: comment on Spillane and Smith (2007).

In their recent article, N. Spillane and G. Smith suggested that reservation-dwelling American Indians have higher rates of problem drinking than do either non-American Indians or those American Indians living in nonreservation settings. These authors further argued that problematic alcohol use patterns in reservation communities are due to the lack of contingencies between drinking and "standard life reinforcers" (SLRs), such as employment, housing, education, and health care. This comment presents evidence that these arguments were based on a partial review of the literature. Weaknesses in the application of SLR constructs to American Indian reservation communities are identified as is the need for culturally contextualized empirical evidence supporting this theory and its application. Cautionary notes are offered about the development of literature reviews, theoretical frameworks, and policy recommendations for American Indian communities.