Effectiveness of manual therapy for patients with low back pain from the perspective of physical and psychosocial factors.

[Purpose] This study aimed to determine the effectiveness of the Arthrokinematic Approach (AKA)-Hakata method for patients with low back pain (LBP). [Participants and Methods] The participants were 39 patients with LBP who visited a medical facility between June 1, 2022, and November 30, 2022. The intervention period was 8 weeks, with five treatment sessions, and the patient assessments were performed using patient self-reported measures of LBP and motor function assessment. [Results] The AKA-Hakata method showed significant differences in all of the items evaluated in the longitudinal comparison of patients. Additionally, an interaction was observed only in the Roland-Morris Disability Questionnaire between the two groups classified using the Subgrouping for Targeted Treatment Back Screening Tool. [Conclusion] The results of this study showed that treatment with the AKA-Hakata method may have an early therapeutic effect on the physical and psychosocial risks in daily life. The results of this study indicated that the AKA-Hakata method is effective for the treatment of LBP. However, this study only evaluated a relatively short treatment period of five sessions. Further research on the long-term treatment effect is needed in order to optimize the treatment duration in detail and investigate the effectiveness of the AKA-Hakata method.

Golfers' Performance Is Improved More by Combining Foam Rolling and Dynamic Stretch to the Lead Hip Than Practice Golf Swinging.

ABSTRACT: Hamada, Y, Akasaka, K, Otsudo, T, Sawada, Y, Hattori, H, Kikuchi, Y, and Hall, T. Golfers' performance is improved more by combining foam rolling and dynamic stretch to the lead hip than practice golf swinging. J Strength Cond Res 38(7): e391-e397, 2024-Warming up is considered effective in improving performance and preventing injury. Despite this, there have been few studies investigating warm-up programs in golf and whether specific factors contribute to improved performance. The purpose of this study was to examine the immediate effects of combined foam rolling and dynamic stretch (FR + DS) to the lead hip on golf swing performance, hip range of motion (ROM), and muscle strength in amateur golfers using a randomized crossover design. The study sample comprised 22 men (mean ± SD ; age, 32.6 ± 8.5 years, body mass index (BMI), 23.4 ± 2.7 kg·m -2 ). Subjects were assigned to receive either FR + DS or repetitive golf swing practice (SW) before crossing over to the other intervention for another day. Measurements included golf swing performance (ball speed, club head speed, flight distance ["carry"], spin rate, and launch angle), hip internal rotation (IR), and external rotation (ER) ROM, as well as hip IR and ER muscle strength. Comparisons between groups were made before and after each intervention. For golf swing performance, FR + DS improved "carry" significantly more than SW ( p < 0.05). No significant differences in golf swing performance other than "carry" were found. In addition, IR ROM and IR muscle strength of the lead hip were significantly increased in the FR + DS group ( p < 0.05). FR + DS has effects on improving lead hip IR ROM and IR muscle strength, which may facilitate golfers' swing and "carry." FR + DS shows promise as a warm-up method for amateur golfers who want to improve golf performance.

Weakening and factors of medial elbow dynamic stabilizers against elbow valgus laxity after repetitive pitching in high school baseball players.

BACKGROUND: Overhead throwing activity induces elbow valgus loading. The medial elbow dynamic stabilizers are thought important for medial elbow joint protection, but the effects of repetitive pitching on stabilizing function are largely unknown. This study aimed to investigate changes in the dynamic stabilizers during repetitive pitching, as well as factors related to dynamic stabilizing ability. Our hypothesis was that repetitive pitching would reduce dynamic stabilizer function, hence reducing the ability to minimize elbow valgus load. METHODS: Thirty high school baseball pitchers (age, 16.6 ± 0.5 years) participated. Each participant pitched 100 times (5 blocks of 20 pitches). Prior to and after 100 pitches, medial elbow joint width and strain ratios, indicating the hardness of the ulnar collateral ligament (UCL) and forearm flexor-pronator muscles (FPMs), were measured using ultrasound at rest (non-contraction) and during gripping (contraction). Pre- and post-pitching data were compared using the paired t test. Multiple regression analysis was used to investigate factors related to the change rate of medial elbow joint width during gripping. RESULTS: Medial elbow joint width during gripping significantly increased from before pitching to after pitching (P < .001). Both the UCL and FPM strain ratios after pitching significantly decreased (ie, softer tissue) compared with those before pitching (P = .001 and P = .006, respectively). The ratio of the UCL and FPM strain ratios (UCL/FPM) during gripping prior to pitching was significantly and independently correlated with the change rate of medial elbow joint width during gripping (ß = 0.44, P = .016). CONCLUSION: Pitching 100 balls induces a significant reduction in dynamic stabilizing ability against elbow valgus laxity. High school baseball pitchers should limit themselves to <100 pitches per game or should rest after 100 pitches before resuming. Furthermore, the ratio of hardness (UCL/FPM) during dynamic stabilization associated with gripping prior to pitching was significantly related to the change rate of elbow valgus laxity during dynamic stabilization. Maintaining the FPMs harder relative to the UCL during gripping prevents elbow valgus laxity associated with repetitive pitching and may protect the medial elbow joint during repetitive pitching.

Effectiveness of an educational approach between adolescents and adults with patellofemoral pain syndrome: a scoping review with meta-analysis.

[Purpose] This study aimed to compare the effectiveness of an educational approach between adolescents and adults with patellofemoral pain syndrome. [Participants and Methods] The PROSPERO protocol number is CRD42022362680. Four databases (PubMed, CINAHL, Scopus, Cochrane) were searched. Randomized control trials on the effectiveness of the educational approach for patellofemoral pain syndrome were compared between adolescents and adults. Two investigators independently screened eligible studies. Two randomized control trials proceeded through meta-analysis with a visual analogue scale in the mid-term (from 18 weeks to 6 months). [Results] The meta-analysis results indicated that no significant difference was observed between education and combined education with exercise. A tendency to improve in the intervention of combined education with exercise for adolescents was noted, whereas no effect of education for adults was observed. [Conclusion] Treatment strategies combining education with exercise for patellofemoral pain syndrome may differ between adolescents and adults.

Immediate Effects of Foam Roller and Stretching to the Lead Hip on Golfers Swing: A Randomized Crossover Trial.

Golfers with decreased range of motion (ROM) of their leading hip internal rotation (IR) have increased lumbar rotation ROM and load. This study investigated the effects of foam roller (FR) applied to their leading hip muscles combined with stretching to the leading hip together with lumbar rotation ROM during the golf swing. The study design was a crossover design. Subjects were allocated to one of two groups comprising FR and dynamic stretching (FR + DS) or practice swing. Motion analysis was used to evaluate hip and lumbar angles during the golf swing. Data were compared using analysis of variance with Bonferroni correction using paired t-test's post hoc. The association between lead hip IR angle and lumbar spine left rotation (Lrot) angle was investigated using correlation analysis. Lead hip IR ROM during the golf swing was significantly greater in the FR + DS group (p = 0.034). The FR + DS group showed a moderate negative correlation between lead hip IR ROM and lower lumbar spine Lrot ROM during the golf swing (r = -0.522). The application of FR + DS might be useful to increase lead hip IR angle during the golf swing. Moreover, the application of FR + DS improves lead hip IR angle and may decrease lumbar spine rotation.

Changes in Medial Elbow Joint Parameters Due to Selective Contraction of the Forearm Flexor-Pronator Muscles.

The harder the forearm flexor-pronator muscles (FPMs) relative to the ulnar collateral ligament (UCL), the less likely it is for UCL laxity to occur with repeated pitching. This study aimed to clarify what selective contraction of the forearm muscles makes FPMs harder relative to UCL. The study evaluated 20 elbows of male college students. Participants selectively contracted the forearm muscles in eight conditions under gravity stress. The medial elbow joint width and the strain ratio indicating tissue hardness of the UCL and FPMs during contraction were evaluated using an ultrasound system. Contraction of all FPMs (in particular flexor digitorum superficialis [FDS] and pronator teres [PT]) decreased the medial elbow joint width compared to rest (p < 0.05). UCL hardens due to the contraction involving the FDS muscle (p < 0.05). FPMs harden due to the contraction of flexor carpi ulnaris (FCU) and FDS (p < 0.05). In the ratio of strain ratio UCL/FPMs, there was no significant difference between rest and each contraction task (p > 0.05). However, contractions composed of FCU and PT tended to harden FPMs relative to the UCL. FCU and PT activation may be effective in UCL injury prevention.

Relationship between Isokinetic Trunk Muscle Strength and Return to Sports Competition after Conservative Therapy in Fresh Cases of Lumbar Spondylolysis: A Retrospective Observational Study.

This study aimed to clarify the relationship between isokinetic trunk muscle strength and return to sporting activities in fresh cases of lumbar spondylolysis treated with conservative therapy. Patients included a total of ten men (age: 13.5 ± 1.7) who were instructed by their attending physicians to stop exercising and who met the eligibility criteria. Isokinetic trunk muscle strength was measured immediately after exercising for the first time (First) and one month (1M). Flexion and extension and maximum torque/body weight ratio were significantly lower First compared to 1M at all angular velocities (p < 0.05). Maximum torque generation time was significantly lower for First at 120°/s and 180°/s than at 1M (p < 0.05). Correlations with the number of days to return to sports competition were detected at 60°/s for maximum torque generation time (p < 0.05, r = 0.65). Following conservative treatment for lumbar spondylolysis, it was considered necessary to focus on trunk flexion and extension muscle strength and contraction speed of trunk flexors at the beginning of the exercise period. It was suggested that trunk extension muscle strength in the extension range might be one of the critical factors for returning to sports.

Comparison of elbow valgus laxity and medial elbow stabilizer parameters during repetitive pitching between high school baseball players with and without a history of medial elbow injury.

BACKGROUND: Adolescent baseball players with a history of medial elbow injury are often reinjured during demanding practice sessions or games. The physical characteristics of baseball players with a history of medial elbow injury have been reported in several previous studies, but the nature of their medial elbow stabilizers is unknown. This study investigated the difference in characteristics of elbow valgus laxity and medial elbow stabilizer parameters between baseball players with and without a history of medial elbow injury, prior to and during repetitive pitching. METHODS: Sixteen high school baseball players with no history of medial elbow injury (No-Injury group) and 14 high school baseball players with a history of medial elbow injury (Injury History group) participated. The participants pitched 100 fastballs. Medial elbow joint-space gapping and strain ratio indicating tissue elasticity of ulnar collateral ligament (UCL) and forearm flexor-pronator muscles (FPMs) were measured by ultrasound before pitching and following each of five 20-pitch blocks. Student t tests and Mann-Whitney U tests were used to compare each parameter between groups. RESULTS: Medial elbow joint-space gapping and UCL elasticity were not significantly different between the 2 groups in each pitching block (P > .05). The strain ratio of FPMs before pitching and after 100 pitches in the Injury History group were significantly greater than that in the No-Injury group (No-Injury vs. Injury History group: before pitching, 0.47 ± 0.19 vs. 0.68 ± 0.26, P = .016; 100 pitches, 0.35 ± 0.12 vs. 0.53 ± 0.20, P = .007). In the other pitching blocks, there was no significant difference between groups, but the effect size was medium and showed a similar tendency (20 pitches, P = .069, Cohen d = 0.69; 40 pitches, P = .116, Cohen d = 0.59; 60 pitches, P = .102, Cohen d = 0.62; 80 pitches, P = .058, Cohen d = 0.72). CONCLUSIONS: The results of this study indicate that FPM elasticity at baseline and during repetitive pitching in players with a history of medial elbow injury was harder than in players without injury history. This may suggest that baseball players with a history of medial elbow injury increase support of their previously injured medial elbow by hardening FPM elasticity to counteract elbow valgus stress generated during pitching, which may lead to long-term change in the FPMs. Therefore, physical management for this change may be important to prevent reinjury in baseball players with a history of medial elbow injury.

Effects of a Groin Pain Prevention Program in Male High School Soccer Players: A Cluster-Randomized Controlled Trial.

Background: Groin pain is frequently reported by soccer players. A prevention program incorporating the Copenhagen adduction exercise (CAE) has been shown effective in decreasing adductor muscle injury in semi-professional soccer players. However, the effect of such programs on groin pain in high school soccer players is unknown. No reports have examined the effects of combining the CAE with other targeted exercises such as the Nordic hamstrings exercise (NHE). Purpose: To evaluate the preventative effects of exercise on groin pain in high school soccer players in three groups comprising NHE alone, combined NHE and CAE, and a control group. Design: Randomized Controlled Clinical Trial. Methods: A cluster randomized controlled trial spanning 16 weeks was conducted on 202 high school soccer players from seven high schools in a Japanese under 18 Soccer League. Players were allocated to either group A (three schools, 66 players) receiving the CAE alone, or group B (two schools, 73 players) receiving the CAE and NHE, or control group C (two schools, 63 players) who performed their usual training. This study compared the number of injuries, injury rate, and severity of the injury of groin pain in these three groups. Results: The number of players injured was less in group B (4 players) compared to C (18 players), and time-lost to soccer was less in groups A (6 players) and B (3 players) compared to group C (16 players). Injury rates were significantly lower in groups A and B, with the relative risk of injury compared to group C of 0.42 (95% CI 0.19% to 0.90%) in group A and 0.19 (95% CI 0.07 to 0.54) in group B. Conclusion: A 16-week program incorporating the CAE in training sessions in high school soccer players reduced the incidence of groin pain and which may be related to injury severity according to time -lost to soccer, however the combination of both the CAE and NHE may be more effective than the CAE alone. Level of Evidence: 2b.

Ir-Catalyzed cyclization of α,ω-dienes with an N-methyl group via two C-H activation steps.

Iridium-catalyzed sp3 C-H alkylation of an N-methyl group with 1,5- and 1,6-dienes proceeded to give five- and six-membered carbocyclic compounds, respectively, in high yields. The reaction involves intermolecular alkylation of the N-methyl group with a vinyl moiety and subsequent intramolecular cyclization at the ß-position of the initially formed alkylated intermediate. The reaction using a chiral bidentate phosphine ligand enabled the asymmetric synthesis of the cyclic compounds.

Determining a preventive strategy for ankle sprain injury through a questionnaire survey of coaches of junior high school basketball teams.

[Purpose] The purpose of this study was to determine a preventive strategy for ankle sprain injury through a questionnaire survey of coaches of junior high school basketball teams. [Participants and Methods] The questionnaire comprised questions concerning coaches' characteristics, prevention-related content, and collaboration with medical staff. We distributed the questionnaire to 108 coaches, of which 48 (41.7%) responded. [Results] The results revealed that none of the participant coaches had ever collaborated with medical staff. [Conclusion] Additional effort from medical staff is needed to hold seminars and contact coaches of junior high school teams in order to conduct an injury prevention program.

Effects of functional movement screen training in high-school baseball players: A randomized controlled clinical trial.

BACKGROUND: In recent years, the functional movement screen (FMS) and FMS training have attracted attention as a means of preventing injury, but no studies have examined the effect of such training in high-school baseball players. The aim of this study was to clarify the effect of FMS training on FMS score, physical function and baseball performance in high-school baseball players. METHODS: Subjects in this randomized controlled clinical trial were high-school male baseball players assigned to either an FMS training group (intervention group) or a control group. The intervention group performed FMS training 4 times per week for 12 weeks. FMS ability, physical function, and baseball performance were measured prior to the intervention, 8, 12, and 24 weeks after the intervention in the subjects' school environment. RESULTS: A total of 71 baseball players aged 15 to 17 years were recruited and assigned to either an intervention group (n = 37) or control group (n = 34). There was no significant difference in the characteristics of participants between the 2 groups. Most FMS scores improved to 12 weeks after continued training. In the intervention group compared with the control group, deep squat, hurdle step, inline lunge, active straight leg raise, trunk stability push-up and rotary stability FMS score, total FMS score and eyes closed single leg stance time significantly increased after 8 weeks of training. While hurdle step, inline lunge, active straight leg raise, trunk stability push-up, total FMS score, and eyes closed single leg stance time significantly increased, pitching ball speed significantly decreased at the end of the 12 week training period. Eyes closed single leg stance time and feeling of fatigue significantly improved 12 weeks after training. The number of subjects who scored less than 14 for the total FMS score in the intervention group compared with control group were significantly less after 8 and 12 weeks of FMS training. CONCLUSION: FMS training for 8 weeks contributes to improving FMS scores for high-school baseball players, but FMS scores go down if FMS training is not continued. TRIAL REGISTRATION: University Hospital Medical Information Network Center, Tokyo, Japan: UMIN000027553. Registered on May 30, 2017.

Ulnar Collateral Ligament Laxity After Repetitive Pitching: Associated Factors in High School Baseball Pitchers.

BACKGROUND: Medial elbow injury is common in baseball pitchers, with evidence of elbow valgus instability after only 60 consecutive pitches. However, the tissue-specific effects of repetitive pitching on medial elbow stabilizers are largely unknown. PURPOSE/HYPOTHESIS: This study aimed to investigate changes in the ulnar collateral ligament (UCL) and forearm flexor-pronator muscles (FPMs) during repetitive pitching and factors that relate to identified change. We hypothesized that repetitive pitching would increase elasticity of the medial elbow stabilizers and therefore induce laxity. STUDY DESIGN: Descriptive laboratory study. METHODS: A total of 30 high school baseball pitchers participated (mean ± SD age, 16.6 ± 0.5 years). Each participant pitched 100 times (5 blocks of 20 pitches). The strain ratio, indicating elasticity in the UCL and FPMs, was measured using ultrasound before pitching and after every 20-pitch block. Data for each pitch block were compared using analysis of variance. Multiple regression analysis was used to investigate factors related to the change rate of the strain ratio. RESULTS: The strain ratio of the UCL after 100 pitches was significantly less than that before pitching (before pitching, 4.83 ± 1.70; after 100 pitches, 3.59 ± 1.35; P = .013), but this was not the case for the FPMs (before pitching, 0.57 ± 0.24; after 100 pitches, 0.43 ± 0.18; P = .07). The ratio of the strain ratio in the UCL and FPMs (UCL/FPMs) before pitching (ß = -0.385; P = .031) and the elbow flexion range of motion before pitching (ß = -0.352; P = .046) were significantly and independently correlated with the change rate of the UCL. CONCLUSION: Elasticity significantly increased for the UCL, indicating laxity, but not for the FPMs after 100 pitches. Furthermore, the ratio of elasticity (UCL/FPMs) and the elbow flexion range of motion before pitching were significantly related to the change rate of UCL elasticity. CLINICAL RELEVANCE: To reduce laxity of the UCL, pitchers should be limited to <100 pitches per game. Sustaining a lower level of relative FPMs to UCL elasticity at rest and maintaining a large muscle volume to avoid excessive elbow flexion range of motion may prevent UCL laxity that develops during repetitive pitching.

Grip strength is not related to increased medial elbow joint-space gapping induced by repetitive pitching.

BACKGROUND: Pitching induces elbow valgus stress, which can lead to an increase in medial elbow joint-space gapping when repeated. Previous basic research on the medial elbow joint shows that the contraction associated with gripping reduces medial elbow joint-space gapping. However, no studies have investigated the relationship between grip strength and increased medial elbow joint-space gapping during repetitive pitching. The purpose of this study was to investigate whether grip strength is related to medial elbow joint-space gapping during repetitive pitching. Our hypothesis was that increased grip strength would correlate with a reduction in medial elbow joint-space gapping. METHODS: A total of 25 high school baseball players participated in this study. Each subject pitched 100 times. The medial elbow joint-space gapping and grip strength were measured before and after pitching. Correlation analysis was used to identify the relationship between medial elbow joint-space gapping and grip strength. RESULTS: Medial elbow joint-space gapping (mm) increased by 25.5% ± 8.0% after 100 pitches (gapping before, 5.0 ± 0.9; gapping after, 6.2 ± 1.1; P < .001). Grip strength (kg) after 100 pitches decreased by 2.8% ± 7.4% to that before pitching (before, 40.4 ± 5.5; after 39.2 ± 5.6; P < .05). There was no significant correlation between the change rate of medial elbow joint gapping and grip strength at any time (grip strength: before pitching, P = .74; after pitching, P = .40; change rate from before to after pitching, P = .24). CONCLUSIONS: Grip strength is not related to increased medial elbow joint-space gapping induced by repetitive pitching. This indicates that physical ability expressed by grip strength is not associated with preventing increases in medial elbow joint-space gapping during repetitive pitching. Further studies are required to investigate the stabilization mechanism of the medial elbow joint during pitching.

Changes in medial elbow elasticity and joint space gapping during maximal gripping: reliability and validity in evaluation of the medial elbow joint using ultrasound elastography.

BACKGROUND: Medial elbow injuries are common in baseball pitchers. This study investigated the reliability of medial elbow elastography measurement and the characteristics of the medial elbow stabilizers. METHODS: Medial elbow joint space gapping and the strain ratios of the ulnar collateral ligament (UCL) and the forearm flexor-pronator muscle (FPM) were measured at rest and during gripping in 29 healthy college students. The intraclass correlation coefficients of elastography were calculated. The data were compared between tissues and between rest and gripping. RESULTS: The intraclass correlation coefficients (ICC1,3) of the elastography measurements were 0.91 and 0.83 for the UCL and 0.80 and 0.85 for the FPM for each examiner. Medial elbow joint space gapping during gripping (3.1 ± 0.6 mm) was significantly less than that at rest (3.8 ± 0.8 mm, P < .001). The strain ratios for both the UCL and FPM during gripping were significantly greater than those at rest (17.64 ± 10.97 during gripping vs. 3.94 ± 1.92 at rest for UCL, P < .001; 1.72 ± 0.99 during gripping vs. 0.35 ± 1.92 at rest for FPM, P < .001). The strain ratio for the UCL was significantly greater than that for the FPM both at rest (P < .001) and during gripping (P < .001). CONCLUSIONS: Elastography measurements of the UCL and FPM have almost perfect reliability. Gripping reduces medial elbow joint space gapping compared with rest. For both tissues, gripping reduces their elasticity compared with rest. The elasticity of the UCL is less than that of the FPM both at rest and during gripping.

Use of an Elbow Brace During Repetitive Pitching Does Not Cause an Increased Mechanical Burden on the Throwing Arm.

BACKGROUND: Repetitive pitching induces an increase in medial elbow joint space gapping and may consequently lead to local tissue stress and injury. Use of an elbow brace may prevent this from occurring by preventing an increase of medial elbow joint space gapping. However, an elbow brace adds weight to the limb and may increase the burden on the throwing arm. OBJECTIVE: To investigate whether use of an elbow brace during repetitive pitching reduces shoulder and arm range of motion and grip strength. DESIGN: Prospective crossover study. SETTING: University campus. PARTICIPANTS: Twenty-five healthy high school baseball players. METHODS: Each participant pitched 100 times under two conditions: without an elbow brace (control) and wearing an elbow brace. MAIN OUTCOME MEASUREMENTS: Shoulder and elbow range of motion (ROM) before pitching and after every block of 20 pitches. Grip strength before pitching and after 100 pitches. RESULTS: There was no significant main effect and interaction for ROM between the two conditions and between pitching sets. In both conditions, grip strength after 100 pitches was significantly lower than that before pitching (P < .05). When the two conditions were compared, there was no significant difference before pitching or after 100 pitches. CONCLUSIONS: Use of elbow brace does not alter shoulder and elbow ROM or decrease grip strength after repetitive pitching up to 100 times compared with a no brace condition. An elbow brace can be used during repetitive pitching without causing an increased mechanical burden on the throwing arm. LEVEL OF EVIDENCE: II.

Three-Dimensional Motion Analysis of the 2nd Cervical Spinous Process at End Range Cervical Rotation in Different Scapular Positions Using 3D Digitizer.

OBJECTIVE: The study used a 3D digitizer to determine three-dimensional motion analysis of the 2nd cervical (C2) spinous process at end range cervical rotation with the scapula in different positions. METHODS: 30 healthy adults participated in this study. Different scapula positions were adopted bilaterally and positioned passively at normal resting, depression, adduction, and abduction. Under each scapula position, bilateral end range cervical rotation and displacement of the C2 spinous process were analyzed by a 3D digitizer. RESULTS: Displacement of the C2 spinous process relative to the occiput was significantly correlated with range of cervical rotation under all scapular positions (p<0.05). However, there were no significant differences between end range cervical rotation and displacement of the C2 spinous process relative to the occiput in any scapular position. CONCLUSION: These results suggest that measurement of upper cervical mobility using the 3D digitizer is a reliable method that holds promise in the evaluation of people with cervical spine disorders.

The effect of repetitive baseball pitching on medial elbow joint space gapping associated with 2 elbow valgus stressors in high school baseball players.

BACKGROUND: To prevent elbow injury in baseball players, various methods have been used to measure medial elbow joint stability with valgus stress. However, no studies have investigated higher levels of elbow valgus stress. This study investigated medial elbow joint space gapping measured ultrasonically resulting from a 30 N valgus stress vs. gravitational valgus stress after a repetitive throwing task. METHODS: The study included 25 high school baseball players. Each subject pitched 100 times. The ulnohumeral joint space was measured ultrasonographically, before pitching and after each successive block of 20 pitches, with gravity stress or 30 N valgus stress. Two-way repeated measures analysis of variance and Pearson correlation coefficient analysis were used. RESULTS: The 30 N valgus stress produced significantly greater ulnohumeral joint space gapping than gravity stress before pitching and at each successive 20-pitch block (P < .01). For the 2 stress methods, ulnohumeral joint space gapping increased significantly from baseline after 60 pitches (P < .01). Strong significant correlations were found between the 2 methods for measurement of medial elbow joint space gapping (r = 0.727-0.859, P < .01). CONCLUSIONS: Gravity stress and 30 N valgus stress may produce different effects with respect to medial elbow joint space gapping before pitching; however, 30 N valgus stress appears to induce greater mechanical stress, which may be preferable when assessing joint instability but also has the potential to be more aggressive. The present results may indicate that constraining factors to medial elbow joint valgus stress matched typical viscoelastic properties of cyclic creep.

The Effects of Elbow Bracing on Medial Elbow Joint Space Gapping Associated With Repetitive Throwing in High School Baseball Players.

BACKGROUND: Throwing athletes risk medial elbow injury from extreme valgus stress generated across the medial elbow during throwing. Braces have been developed to protect the elbow joint; however, no previous study has investigated the effects of elbow bracing on medial elbow joint space gapping associated with repetitive throwing. HYPOTHESIS/PURPOSE: The purpose of this study was to investigate the effects of elbow bracing on medial elbow joint space gapping during repetitive throwing. Our hypothesis was that an elbow brace may reduce mechanical stress on the elbow by reducing medial elbow joint space gapping. STUDY DESIGN: Controlled laboratory study. METHODS: Twenty-five high school baseball players participated in this study. Each subject pitched 100 times under 2 conditions: control (without elbow brace) and elbow brace. The ulnohumeral joint space was measured ultrasonically before pitching and after every block of 20 pitches. Measurement of the ulnohumeral joint space was carried out using ultrasound with the forearm hanging by the side. Two-way repeated-measures analysis of variance and post hoc tests were used to compare ulnohumeral joint space with repeated pitching and between the elbow brace and control conditions. RESULTS: In the control condition, ulnohumeral joint space after 60 pitches was significantly greater than that before pitching (P < .01). In contrast, in the elbow brace condition, ulnohumeral joint space was not significantly different after repeated pitching. When comparing these 2 conditions, ulnohumeral joint space in the control condition was significantly greater than that in the elbow brace condition after 60 pitches (P < .01). CONCLUSION: An elbow brace has the effect of preventing medial elbow joint space gapping with repeated throwing when determined ultrasonically by measuring the ulnohumeral joint space under gravity load. CLINICAL RELEVANCE: An elbow brace worn during baseball pitching practice may help reduce mechanical stress on the elbow by reducing medial elbow joint space gapping.

T-817MA, a novel neurotrophic agent, ameliorates loss of GABAergic parvalbumin-positive neurons and sensorimotor gating deficits in rats transiently exposed to MK-801 in the neonatal period.

T-817MA [1-{3-[2-(1-benzothiophen-5-yl)ethoxy]propyl}azetidin-3-ol maleate] is a newly synthesized neuroprotective agent for the treatment of psychiatric disorders characterized by cognitive disturbances, such as Alzheimer's disease. Cognitive impairment has also been suggested to be a cardinal feature of schizophrenia. We sought to determine whether T-817MA would ameliorate sensorimotor gating deficits and loss of parvalbumin (PV)-positive γ-aminobutyric acid (GABA) neurons in the brain of rats transiently exposed to MK-801, an N-methyl-d-aspartate receptor blocker, in the neonatal stage, as an animal model of schizophrenia. Prepulse inhibition (PPI) was examined in rats treated neonatally with MK-801 (postnatal day; PD 7-10, 0.2 mg/kg/day, s.c.) or vehicle at PD 35 and PD 63. The number of PV-positive GABAergic neurons in the medial prefrontal cortex (mPFC) and the hippocampus was measured after the behavioral assessments. T-817MA (10 or 20 mg/kg) or vehicle was administered for 14 days (on PD 49-62). Administration of T-817MA at 20 mg/kg, but not 10 mg/kg, ameliorated PPI deficits and completely reversed the decrease in the number of PV-positive GABAergic neurons in rats given MK-801. These results indicate that T-817MA may provide a novel therapeutic approach for the treatment of cognitive deficits of schizophrenia.