Pool-Based Surfboard Elicits Activation of Posterior Shoulder Muscles During a Surfing Stroke.

ABSTRACT: Pexa, BS, Johnston, CD, Elder, EE, Ford, KR, Patterson, MQ, and Myers, JB. Pool-based surfboard elicits activation of posterior shoulder muscles during a surfing stroke. J Strength Cond Res 38(7): 1300-1304, 2024-Surfboard paddling may activate posterior shoulder muscles, which are critical to baseball pitchers' injury risk and performance. The purpose of this study was to measure posterior shoulder muscle activation during different phases of the surf stroke (propulsion vs. recovery) on a pool-based surfboard. Twenty healthy active adult subjects completed a familiarization and testing session with the pool-based surfboard. During the testing session, electromyography (EMG) sensors were placed on 6 posterior shoulder muscles: latissimus dorsi, infraspinatus, posterior deltoid, upper trapezius, middle trapezius, and lower trapezius. Subjects completed 4 laps in a pool at 3 separate resistances (low, moderate, and heavy) in a randomized order. The peak EMG signal during each phase (propulsion and recovery) was recorded. A 2-way within subject ANOVA (resistance-by-phase) with post hoc Bonferroni's corrections was used to identify differences in EMG activation. There was a significant main effect of phase for the latissimus dorsi (F = 91.3, p < 0.001), upper trapezius (F = 36.5, p < 0.001), middle trapezius (F = 33.8, p < 0.001), and lower trapezius (F = 21.6, p < 0.001). The latissimus dorsi demonstrated higher activation during the propulsion phase (p < 0.001), and all trapezius muscles demonstrated higher activation during the recovery phase (p < 0.001). There was a significant main effect of resistance for the posterior deltoid (F = 3.4, p = 0.043), with higher muscle activation in the low resistance trials compared with the heavy resistance trials (p = 0.036). Recreationally active individuals demonstrate activation of the posterior shoulder when using a pool-based surfboard. This pool-based surfboard may be beneficial to activate the posterior musculature and may be more accessible than standard surfing to baseball athletes.

Vibration improves gait biomechanics linked to posttraumatic knee osteoarthritis following anterior cruciate ligament injury.

Anterior cruciate ligament reconstruction (ACLR) incurs a high risk of posttraumatic knee osteoarthritis (PTOA). Aberrant gait biomechanics contribute to PTOA and are attributable in part to quadriceps dysfunction. Vibration improves quadriceps function following ACLR, but its effects on gait biomechanics are unknown. The purpose of this study was to evaluate the effects of whole-body vibration (WBV) and local muscle vibration (LMV) on gait biomechanics in individuals with ACLR. Seventy-five volunteers (time since ACLR 27 ± 16 months) were randomized to WBV, LMV, or Control interventions. Walking biomechanics were assessed prior to and following a single exposure to the interventions. Outcomes included pre-post change scores in the ACLR limb for the peak vertical ground reaction force (vGRF) and its loading rate, peak internal knee extension (KEM) and abduction moments, and peak knee flexion and varus angles. LMV produced a significant decrease in the vGRF loading rate (-3.6 BW/s) that was greater than the changes in the WBV (-0.3 BW/s) and Control (0.5 BW/s) groups. Additionally, WBV produced an increase in the peak KEM (0.27% BW × Ht) that was greater than the change in the Control group (-0.17% BW × Ht) but not the LMV group (0.01% BW × Ht). Lower KEM and greater loading rates have been linked to declines in joint health following ACLR. WBV acutely increased the peak KEM and LMV decreased loading rates. These data suggest that vibration has the potential to mitigate aberrant gait biomechanics, and may represent an effective approach for reducing PTOA risk following ACLR.

Somatosensory Function Influences Aberrant Gait Biomechanics Following Anterior Cruciate Ligament Reconstruction.

Osteoarthritis is common following anterior cruciate ligament reconstruction (ALCR), and aberrant gait biomechanics are considered a primary contributor. Somatosensory dysfunction potentially alters gait biomechanics, but this association is unclear. Therefore, the purposes of this investigation were to compare somatosensory function between limbs and evaluate associations between somatosensory function and gait biomechanics linked to osteoarthritis development in individuals with ALCR. Seventy-three volunteers with ALCR participated. Gait biomechanics (peak vertical ground reaction force magnitude and loading rate, peak internal knee extension and valgus moments, peak knee flexion and varus angles, and quadriceps/hamstrings co-activation) were assessed as subjects walked at their preferred speed. The somatosensory function was assessed via joint position sense error (knee flexion) and vibratory perception threshold (femoral epicondyles, malleoli, and first metatarsal). Though somatosensory function did not differ between the ACLR and contralateral limbs, poorer joint position sense in the ACLR limb was associated with lower loading rates and internal knee extension moments, and greater co-activation. Poorer vibratory perception at the medial and lateral malleoli and first metatarsal head in the ACLR limb was associated with lower loading rates, greater internal knee valgus moments and varus angles, and greater co-activation. Poorer vibratory perception at the medial malleolus and first metatarsal head in the contralateral limb was associated with greater peak knee varus angles and internal knee valgus moments. These results suggest that future research evaluating rehabilitation approaches for improving somatosensory function is warranted as a potential approach for restoring normal gait biomechanics and reducing osteoarthritis risk. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:620-628, 2020.

Long-term occlusal and soft-tissue profile outcomes after treatment of Class II Division 1 malocclusion with fixed appliances.

INTRODUCTION: Our objective was to determine which factors were predictive of good long-term outcomes after fixed appliance treatment of Class II Division 1 malocclusion. METHODS: Two hundred seven patients with Class II Division 1 malocclusion were examined in early adulthood at a mean of 4.6 years after treatment with fixed appliances. The peer assessment rating index was used to evaluate dental alignment and occlusal relationships. The soft-tissue profile was assessed with the Holdaway angle. RESULTS: Logistic regression identified 3 pretreatment variables that were predictive of a good facial profile (Holdaway angle) at recall: the lower lip to E-plane distance (P <0.001; smaller distance behind the E-plane means a better outcome), ANB angle (P = 0.001; smaller ANB means a better outcome), and extraction pattern (P = 0.026). Linear regression analysis showed that 2 pretreatment variables were predictive of a favorable PAR score at recall: SNB angle (P = 0.001; larger SNB means a better outcome) and extraction pattern (P = 0.034). CONCLUSIONS: Three pretreatment cephalometric measures (lower lip to E-plane distance, ANB angle, and SNB angle) were predictive of the outcome in the treatment of Class II Division 1 malocclusion. The extraction pattern was also found to be a predictor of outcome.

Psychological status of patients referred for orthognathic correction of skeletal II and III discrepancies.

OBJECTIVE: To establish the extent of psychological problems among patients who require orthognathic treatment. MATERIALS AND METHODS: Five aspects of psychological functioning were assessed for 162 patients who required orthognathic treatment and compared with 157 control subjects. RESULTS: Analysis of variance did not detect any significant difference in the five psychological scores recorded for the skeletal II, skeletal III, and control groups. The proportion of subjects with one or more psychological measure beyond the normal range was 27% for skeletal II subjects, 25% for skeletal III subjects, and 26% for control subjects. One skeletal II subject (1.5%), three skeletal III subjects (3%), and five control subjects (3%) required referral for psychological counseling. CONCLUSIONS: The orthognathic patients did not differ significantly from the control subjects in their psychological status.

The prevalence of bacteraemia on removal of fixed orthodontic appliances.

This study investigated the prevalence of bacteraemia on removal of fixed appliances. Venous blood samples were taken before and after debonding and debanding for 30 patients (mean age 17 years 8 months) who had worn fixed appliances for an average of 19 months. Before removal of the fixed appliances, bacteraemia was detected in one of the 30 subjects (3%) and in four subjects (13%) following removal of their fixed appliances. The 95 per cent confidence intervals for the prevalence of post-debanding bacteraemia were 3.8 and 30.7 per cent. No significant relationship was detected between the mean plaque scores (t = -0.65, P = 0.52) or the mean gingival scores (t = 0.75, P = 0.46) and the occurrence of bacteraemia. The prevalence of bacteraemia detected following debanding in this study is considerably lower than reported for dental procedures traditionally covered by antibiotic prophylaxis guidelines.

A comparison of craniofacial form in Northern Irish children with unilateral cleft lip and palate treated with different primary surgical techniques.

OBJECTIVE: The quality of outcomes in patients with unilateral cleft lip and palate (UCLP) was compared between two senior plastic surgeons. One surgeon carried out a one-stage Wardill-Kilner palate repair. The other surgeon employed a vomer flap hard palate repair followed by a von Langenbeck soft palate closure (Oslo protocol). DESIGN: Retrospective analysis. PATIENTS: Thirty-four children (mean age 9.7 years) born with complete skeletal UCLP in Northern Ireland from 1983 to 1991 who received primary repair surgery from one of the two surgeons. MAIN OUTCOME MEASURES: Cephalometric analysis was used to determine the craniofacial form and soft tissue profile. The quality of the dental arch relationships was independently assessed using the Goslon ranking system. RESULTS: Twenty-nine of the 34 subjects had good or satisfactory arch relationships. Comparison between the surgeons revealed that the Wardill-Kilner group had a greater proportion of Goslon grades of greater than 3, indicating poor arch relationships. However, this difference failed to reach statistical significance. There were no significant cephalometric differences between patients treated by the two surgeons. CONCLUSIONS: Although the difference was not statistically significant, the highest proportion of patients likely to require orthognathic surgery was found in those treated using the Wardill-Kilner technique.

Mandibular advancement appliances and obstructive sleep apnoea: a randomized clinical trial.

This randomized placebo-controlled cross-over trial assessed the effectiveness of a mandibular advancement appliance (MAA) in managing obstructive sleep apnoea (OSA). Twenty-one adults, with confirmed OSA, were provided with a maxillary placebo appliance and a MAA for 4-6 weeks each, in a randomized order. Questionnaires at baseline and after each appliance assessed bed-partners' reports of snoring severity (loudness and number of nights per week), and patients' daytime sleepiness (Epworth Sleepiness Score, ESS). The Apnoea Hypopnoea Index (AHI) and Oxygen Desaturation Index (ODI) were measured at baseline and with each appliance during single night sleep studies. Seventy-nine per cent of subjects wore their MAA for at least 4 hours at night. Sixty-eight per cent of subjects wore their MAA for 6-7 nights per week. Excessive salivation was the most commonly reported complication. One subject was unable to tolerate the MAA and withdrew from the study. Among the remaining 20 subjects, the MAA produced significantly lower AHI and ODI values than the placebo. However, although the reported frequency and loudness of snoring and the ESS values were lower with the MAA than the placebo, these differences were not statistically significant. When wearing the MAA, 35 per cent of the OSA subjects had a reduction in the pre-treatment ODI to 10 or less, while 33 per cent had an AHI of 10 or less. The MAA was less effective in the subjects with the most severe OSA (pre-treatment ODI > 50 and/or pre-treatment AHI > 50).