Changes in Manipulative Peak Force Modulation and Time to Peak Thrust among First-Year Chiropractic Students Following a 12-Week Detraining Period.

OBJECTIVE: The purpose of this study was to analyze differences in peak force modulation and time-to-peak thrust in posterior-to-anterior (PA) high-velocity-low-amplitude (HVLA) manipulations in first-year chiropractic students prior to and following a 12-week detraining period. METHODS: Chiropractic students (n=125) performed 2 thrusts prior to and following a 12-week detraining period: total peak force targets were 400 and 600 N, on a force-sensing table using a PA hand contact of the participant's choice (bilateral hypothenar, bilateral thenar, or cross bilateral). Force modulation was compared to defined target total peak force values of 600 and 400 N, and time-to-peak thrust was compared between data sets using 2-tailed paired t-tests. RESULTS: Total peak force for the 600 N intensity varied by 124.11 + 65.77 N during the pre-test and 123.29 + 61.43 N during the post-test compared to the defined target of 600 N (P = .90); total peak force for the 400 N intensity varied by 44.91 + 34.67 N during the pre-test and 44.60 + 32.63 N during the post-test compared to the defined target of 400 N (P = .57). Time-to-peak thrust for the 400 N total peak force was 137.094 + 42.47 milliseconds during the pre-test and 125.385 + 37.46 milliseconds during the post-test (P = .0004); time-to-peak thrust for the 600 N total peak force was 136.835 + 40.48 milliseconds during the pre-test and 125.385 + 33.78 milliseconds during the post-test (P = .03). CONCLUSIONS: The results indicate no drop-off in the ability to modulate force for either thrust intensity, but did indicate a statistically significant change in time-to-peak thrust for the 400 N total peak force thrust intensity in first-year chiropractic students following a 12-week detraining period.

BIOMECHANICAL MATCHING OF LOW BACK EXTERNAL DEMANDS DURING THE OPEN- AND CLOSED-CHAIN SIDE BRIDGE.

BACKGROUND: The side-bridge (SB) is a commonly used closed-chain task to assess trunk muscle endurance and side-to-side endurance asymmetry. An open-chain variation of the SB, that positions the participant in an inclined side-lying posture, may be useful for those who report shoulder pain or fatigue as the reason for terminating the closed-chain SB. Low back loading demands of the open- and closed-chain variations should be matched to facilitate comparison of SB endurance measures. PURPOSE: To quantify the low back reaction moments during the open- and closed-chain SB and determine the appropriate open-chain angle of inclination that matches the lateral bend moment magnitude of the closed-chain SB. STUDY DESIGN: Observational cohort. METHODS: Upper body and trunk postural data were obtained during the closed-chain SB and during the open-chain SB at each of four inclination angles from a group of eight healthy male adults. Ground reaction force (GRF) data were also collected during the closed-chain SB. Low back reaction moments were calculated using a static 'top-down' linked segment model in both SB variations. Latent growth modeling was used to determine the angle of inclination in the open-chain SB that produced a low back lateral bend moment that matched the closed-chain SB. Sensitivity of the matching open-chain inclination angle was evaluated by rotating the measured GRF vector from the closed-chain SB by five degrees clockwise and counter-clockwise in the frontal plane. RESULTS: The open-chain inclination angle that best matched the loading demands of the closed-chain SB was 38 ± 12 degrees. Clockwise rotation of the measured GRF in the closed-chain SB increased the matching inclination angle to 56 ± 17 degrees. Counter-clockwise rotation reduced the matching inclination angle to 17 ± 11 degrees. Secondary descriptive analysis of spine posture and off-axis low back moments revealed biomechanically relevant differences between SB positions. CONCLUSION: The average open-chain SB angle of inclination that matched the closed-chain SB approximated the 45-degree recommendation offered in the literature. Differences in spine posture and off-axis low back reaction moments, and the potential impact on holding times, should be considered if using the open-chain SB. LEVEL OF EVIDENCE: 2b.

Incidence and risk factors for musculoskeletal disorders of the elbow in baseball pitchers: a systematic review of the literature.

OBJECTIVE: To determine the incidence and risk factors of musculoskeletal disorders of the elbow in baseball pitchers. DESIGN: Systematic review. DATA SOURCES: Medline, CINAHL, Cochrane, PubMed and SportDiscus from onset to July 7, 2018. ELIGIBILITY CRITERIA: Eligible studies included randomized controlled trials, cohort studies and case-control studies. Independent pairs of reviewers screened titles and abstracts for eligibility. Relevant articles were critically appraised for internal validity using the SIGN criteria. We included low risk of bias studies in our best evidence synthesis. RESULTS: We retrieved 4502 articles, 39 were critically appraised and nine had a low risk of bias. These were included in the evidence synthesis. The incidence of musculoskeletal disorders of the elbow ranges from 2.3% in adolescent pitchers to 40.6% in youth pitchers. Evidence suggests that pitch characteristics, inadequate rest, biomechanical and anthropometric factors may be risk factors of UCL tears. SUMMARY/CONCLUSION: Baseball pitchers develop musculoskeletal disorders of the elbow. There is little high-quality evidence to understand the etiology. Preliminary evidence suggests the risk factors are multifactorial.PROSPERO Trial Registration Number: CRD42018092081.

OBJECTIF: Établir l'incidence et facteurs de risque de troubles musculosquelettiques du coude chez le lanceur de baseball. MÉTHODOLOGIE: Revue exhaustive. SOURCES DES DONNÉES: Medline, CINAHL, Cochrane, PubMed et SportDiscus depuis le début jusqu'au 7 juillet 2018. CRITÈRES D'ADMISSIBILITÉ: Les études admissibles étaient des essais comparatifs à répartition aléatoire, des études de cohortes et des études de cas-témoins. Des pairs examinateurs indépendants ont trié des titres et des résumés satisfaisant les critères d'admissibilité. On a évalué la validité interne des articles pertinents en utilisant les critères SIGN. On a tenu compte d'un faible risque d'études faussées dans notre meilleure synthèse de preuves. RÉSULTATS: Sur les 4 502 articles retenus, 39 ont été évalués d'une façon critique; neuf présentaient un risque de parti pris. Ceux-ci ont été inclus dans la synthèse de preuves. L'incidence des troubles musculosquelettiques du coude variait de 2,3 % chez les lanceurs adolescents à 40,6 % chez les jeunes lanceurs. Les données semblent indiquer que les caractéristiques du lancer, un repos insuffisant, des facteurs biomécaniques et anthropométriques pourraient être des facteurs de risque de déchirure du ligament collatéral de l'ulna (LCU). RÉSUMÉ/CONCLUSION: Les lanceurs de baseball développent des troubles musculosquelettiques au coude. Il existe peu de preuves de grande qualité permettant de comprendre l'étiologie de ces troubles. Les données préliminaires semblent indiquer que les causes sont multifactorielles.Numéro d'enregistrement d'essai PROSPERO : CRD42018092081.

The effects of spinal manipulation on performance-related outcomes in healthy asymptomatic adult population: a systematic review of best evidence.

Introduction: The effectiveness of spinal manipulative therapy (SMT) for improving athletic performance in healthy athletes is unclear. Assessing the effect of SMT on other performance outcomes in asymptomatic populations may provide insight into the management of athletes where direct evidence may not be available. Our objective was to systematically review the literature on the effect of SMT on performance-related outcomes in asymptomatic adults. Methods: MEDLINE, CINAHL, SPORTDiscus, and Cochrane Central Register of Controlled Trials were systematically searched from 1990 to March 23, 2018. Inclusion criteria was any study examining a performance-related outcome of SMT in asymptomatic adults. Methodological quality was assessed using the SIGN criteria. Studies with a low risk of bias were considered scientifically admissible for a best evidence synthesis. We calculated the between group mean change and 95% confidence intervals. Results: Of 1415 articles screened, 20 studies had low risk of bias, seven were randomized crossover trials, 10 were randomized controlled trials (RCT) and three were RCT pilot trials. Four studies showed SMT had no effect on physiological parameters at rest or during exercise. There was no effect of SMT on scapular kinematics or transversus abdominus thickness. Three studies identified changes in muscle activation of the upper or lower limb, compared to two that did not. Five studies showed changes in range of motion (ROM). One study showed an increase lumbar proprioception and two identified changes in baropodometric variables after SMT. Sport-specific studies show no effect of SMT except for a small increase in basketball free-throw accuracy. Conclusion: The preponderance of evidence suggests that SMT in comparison to sham or other interventions does not enhance performance-based outcomes in asymptomatic adult population. All studies are exploratory with immediate effects. In the few studies suggesting a positive immediate effect, the importance of such change is uncertain. Further high-quality performance specific studies are required to confirm these preliminary findings.

Septic olecranon and prepatellar bursitis in hockey players: a report of three cases.

Septic bursitis (SB) is an important differential diagnosis in athletes presenting with an acute subcutaneous swelling of the elbow or knee. Prompt recognition is essential to minimize recovery time and prevent the spread of infection. Due to the significant overlap in clinical features, it is often difficult to differentiate SB from non-septic bursitis (NSB) without bursal aspirate analysis. SB is commonly not considered unless the bursitis is accompanied by a local skin lesion or fever. This study describes two cases of septic olecranon bursitis and one case of septic prepatellar bursitis in adult hockey players presenting to a sports medicine clinic. None of the cases presented with an observable skin lesion and only one case developed a fever. It is therefore essential that clinicians maintain a high index of suspicion and monitor for signs of progression when presented with an acute bursitis even in the absence of these features.

La bursite septique (BS) est un diagnostic différentiel important chez les athlètes souffrant d'un œdème sous-cutané aigu du coude ou du genou. Le diagnostic rapide est essentiel pour réduire au minimum la période de convalescence et prévenir la propagation de l'infection. En raison du chevauchement important des caractéristiques cliniques, il est souvent difficile de distinguer entre la BS et la bursite non septique (BNS) sans analyse de l'aspiration de la bourse. La bursite septique n'est couramment envisagée que si elle est accompagnée d'une lésion cutanée locale ou de fièvre. Cette étude décrit deux cas de bursite rétro-olécranienne septique et un cas de bursite prérotulienne septique chez les joueurs de hockey adultes qui se présentent à une clinique de médecine sportive. Aucun des cas ne présentait une lésion cutanée observable et un seul cas a présenté de la fièvre. Il est donc essentiel que les cliniciens maintiennent un haut indice de suspicion et surveillent les signes de progression lorsqu'on leur présente une bursite aiguë même en l'absence de ces caractéristiques.