Validating the preoperative Japanese Core Outcome Measures Index for the Neck and comparing quality of life in patients with cervical spondylotic myelopathy and ossification of the posterior longitudinal ligament by the patient-reported outcome measures.

PURPOSE: This cross-sectional study serves two main purposes. Firstly, it aims to validate the preoperative Japanese Core Outcome Measures Index for the Neck (COMI-Neck) in patients with cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL). Secondly, it seeks to elucidate differences in preoperative quality of life (QOL) between these two cervical pathologies using patient-reported outcome measures (PROMs). METHODS: A total of 103 preoperative patients (86 with CSM and 17 with OPLL) scheduled for cervical spine surgery were included in the study. Validated PROMs, including the Japanese COMI-Neck, Neck Disability Index (NDI), EuroQol-5 Dimension-3 level (EQ-5D-3L), and SF-12v2, were used to assess QOL. Baseline demographic and clinical data were collected, and statistical analyses were performed to compare the PROMs between CSM and OPLL groups. RESULTS: The Japanese COMI-Neck demonstrated good construct validity, with positive correlations with NDI and negative correlations with EQ-5D-3L and SF-12v2. Comparison of preoperative PROMs between CSM and OPLL groups revealed differences in age, body mass index, and EQ-5D-3L scores. The CSM group had higher NDI scores for concentration and lower EQ-5D-3L scores for self-care compared to the OPLL group. CONCLUSIONS: This study validated the preoperative Japanese COMI-Neck in CSM and OPLL patients and identified specific QOL issues associated with each condition. The findings highlight the importance of considering disease-specific QOL and tailoring treatment plans accordingly. Further research should include postoperative assessments and a more diverse population to enhance generalizability.

Construct validation of the Japanese Core Outcome Measures Index and the impact of diseases on patient-reported outcome measures in preoperative patients with lumbar spinal stenosis and disk herniation: a single-center observational study.

PURPOSE: The primary objective was to validate the construct validity of the Japanese Core Outcome Measures Index (COMI) in preoperative patients aged 60 years or older undergoing lumbar spine surgery for lumbar spinal stenosis (LSS) and lumbar disk herniation (LDH). Additionally, as a secondary aim, we explored the impact of these diseases on quality of life (QOL). METHODS: The analysis included 199 preoperative patients aged 60 and above who were scheduled for lumbar spine surgery. To assess QOL, Japanese versions of the COMI, Oswestry Disability Index (ODI), EuroQol-5 Dimension-3 Level (EQ-5D-3L), and SF-12v2 were employed. The study assessed the validity of the COMI and compared demographic and clinical characteristics between the LSS (147 cases) and LDH (52 cases) groups. It used multivariate covariance analysis (MANCOVA) to examine the impact of diseases (LSS and LDH) on each patient-reported outcome measure while considering covariates. RESULTS: Compared to the LSS group, the LDH group showed more difficulty with the COMI summary score (LSS/LDH [mean]: 6.9/8.1, p < 0.001), ODI score (46.8/57.4, p < 0.001), and EQ-5D utility (0.53/0.43, p < 0.001). The LDH group also reported more difficulties in the COMI-function, COMI-symptom-specific well-being, COMI-disability, ODI-personal care, ODI-social life, and SF-12v2-bodily pain subscales. MANCOVA demonstrated that these results were not influenced by covariates such as gender and medical history. CONCLUSIONS: This study highlights the distinct impact of LSS and LDH on preoperative QOL in older patients undergoing lumbar spinal surgery. Tailored interventions are essential to address the specific challenges posed by these conditions and improve patient-centered outcomes and postoperative recovery.

Prevalence and associated factors of non-traumatic shoulder pain during spike and serve movements in male high school volleyball players: a cross-sectional study.

BACKGROUND: Nontraumatic shoulder pain is a prevalent issue among male high school volleyball players, but its comprehensive assessment has been lacking in prior research, which often isolated specific aspects of shoulder function. This study aimed to identify contributing factors to shoulder pain in this population. HYPOTHESIS: The hypothesis posited that limited shoulder internal rotation (IR) range of motion (ROM), imbalance in rotator cuff muscle strength, intrinsic sensory disturbance, and joint stability are associated with shoulder pain in male high school volleyball players. Additionally, there was an anticipation that a substantial proportion of players would experience shoulder pain but refrain from reporting it to coaches. METHODS: Forty-nine male volleyball players aged 15-17 years were evaluated between February and June 2023. Questionnaires assessed the prevalence of shoulder pain during spiking and/or serving, as well as the frequency of reporting this pain to coaches. Various factors, including acromio-humeral distance, shoulder ROM, isometric strength, proprioception, joint stability (Upper Quarter Y-Balance Test), joint position sense, and upper extremity power (Seated Medicine Ball Throw Test; SMBT), were quantified. Logistic regression analyses was conducted to explore potential connections between these variables and shoulder pain. RESULTS: Shoulder pain was reported by 39% of participants, but it was rarely communicated to coaches (95%). Jump serves (odds ratio 1.84, p=0.02) and reduced shoulder IR ROM (odds ratio 0.94, p=0.03) were associated with shoulder pain. CONCLUSION: This study provides crucial insights into the prevalence, severity, and associated factors of shoulder pain among male high school volleyball players. The findings underscore the importance of improving athlete-coach communication to facilitate early intervention and preventive measures. Significant associations were observed between the use of jump serves, reduced shoulder internal rotation range of motion, and shoulder pain, highlighting the relevance of specific volleyball techniques in injury prevention. These findings offer valuable guidance to coaches and trainers in developing interventions aimed at mitigating the risk of shoulder pain and enhancing player 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.

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.

Predicting the occurrence of in-season groin pain in male high school soccer players: a cohort study.

[Purpose] This study investigated whether pre-season HAGOS (Japanese Copenhagen Hip and Groin Outcome Scores) and eccentric muscle strength of the hip muscles predict in-season groin pain incidences in high school soccer players. [Participants and Methods] This study had a cohort design. The participants were male high school players under 18 years playing in the Japan Soccer League, which is an elite-level soccer league of that age category in Japan. The HAGOS and the strength of hip abductor and adductor muscles in eccentric contraction were measured before the season, and hip and groin pain incidences were recorded during the season. Multiple logistic regression analysis was performed to investigate the factors derived from the pre-season HAGOS and hip muscle strength tests, presumably pertaining to the development of in-season groin pain. [Results] The eccentric adductor muscle strength of the dominant leg and the HAGOS were selected as factors associated with groin pain during the season. [Conclusion] Low pre-season HAGOS and weak dominant-leg eccentric adductor muscle strength were suggested as factors to predict in-season groin pain occurrence in male high school soccer players.

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.

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 incorporating elliptical trainer exercise during rehabilitation on physical function and self-reported outcomes after total hip arthroplasty: a randomized controlled trial.

[Purpose] To investigate the effects of incorporating elliptical trainer exercise in early rehabilitation after total hip arthroplasty on physical function and self-reported outcomes. [Participants and Methods] Participants with independent gait prior to total hip arthroplasty underwent conventional postoperative physiotherapy and were divided into two groups. The intervention group additionally underwent elliptical trainer exercise, while the control group underwent a walking program. The main outcomes were low back and hip region pain, lower limb muscle strength, single-leg stance time, Timed Up & Go Test results, 10 m walking test results, hip disability and osteoarthritis outcome score, and modified fall efficacy scale score. These outcomes were evaluated preoperatively, at discharge, and at 1 and 3 months postoperatively. [Results] Fifty participants (including 40 females; age, 68.3 ± 10.8 years) participated in this study. Physical function evaluations showed a significant improvement in hip region pain during walking at discharge. Knee extensor strength, single-leg stance time, stride length, and walking speed were significantly greater in the intervention group at discharge and at 1 and 3 months postoperatively. The modified fall efficacy scale score significantly improved in the intervention group 1 month postoperatively. [Conclusion] Elliptical trainer exercise and conventional physiotherapy in the early postoperative period contribute to improved physical function and walking ability and improvement in the fear of falling.

Inter-examiner reliability in identifying lumbar paraspinal muscle atrophy by lumbar paraspinal muscle atrophy index, a novel parameter.

[Purpose] To evaluate the inter-examiner reliability of our novel parameter, the lumbar paraspinal muscle atrophy index, in identifying the lumbar paravertebral muscle atrophy. [Participants and Methods] The study group consisted of 225 adults, with a mean age of 64.7 (range, 21-89) years, who underwent posterior lumbar spinal surgery for degenerative spinal disease at our hospital between July 2013 and June 2017. Preoperative axial T2-weighted magnetic resonance images were used to evaluate the lumbar paraspinal muscle atrophy index and observe the presence or absence of severe lumbar paraspinal muscle atrophy. The lumbar paraspinal muscle atrophy index was calculated at each intervertebral level, from L1-2 through L4-5, once by two examiners, and the Cohen's kappa statistic was used to calculate the inter-examiner agreement of the classification of the presence or absence of atrophy at each level. [Results] The agreement was high (kappa, 0.79-0.88) for the lumbar paraspinal muscle atrophy index at all levels, except at the L3-4 level (kappa, 0.49). The lower kappa statistic at L3-4 likely reflects the unique morphological characteristics at this level. [Conclusion] The lumbar paraspinal muscle atrophy index is a new, simple, easy-to-use, and sufficiently reliable parameter to identify lumbar paraspinal atrophy.

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.

Factors affecting early knee-flexion range of motion after total knee arthroplasty.

[Purpose] To investigate the factors affecting the knee-flexion range of motion in the early period after total knee arthroplasty. [Participants and Methods] Ninety-nine patients who had undergone total knee arthroplasty at our hospital between 2016 and 2019 were allocated into two groups based on the presence of a 110° knee-flexion range of motion at 14 days post-surgery. From medical records, we extracted data for the participants' basic attributes and preoperative/postoperative physical function (knee-flexion range of motion, Timed Up & Go Test results, resting/walking pain according to a numerical rating scale, and knee-extension muscle strength). Postoperative physical function was measured 14 days post-surgery. [Results] Preoperative knee-flexion range of motion, preoperative femorotibial angle, postoperative knee-extensor strength, and postoperative Timed Up & Go Test value differed significantly as factors related to achieving a 110° knee-flexion range of motion. Through further statistical analyses, we selected the preoperative knee-flexion range of motion, preoperative femorotibial angle, preoperative Timed Up & Go Test result, and postoperative knee-extension strength as factors affecting the knee-flexion range of motion at 14 days post-surgery. [Conclusion] Preoperative knee-flexion range of motion, preoperative femorotibial angle, preoperative Timed Up & Go Test result, and postoperative knee-extension strength influence knee-flexion range of motion at 14 days after total knee arthroplasty, and our findings indicate the effectiveness of active physiotherapy interventions.

Quality of life and life-space mobility after total knee arthroplasty in patients with rheumatoid arthritis: a pilot case-controlled study.

[Purpose] The purpose of this study was to identify factors inhibiting improvement in the quality of life after total knee arthroplasty in patients with rheumatoid arthritis. [Participants and Methods] This was a pilot case-control study. The sample comprised of five participants with rheumatoid arthritis and 11 participants with osteoarthritis, who underwent total knee arthroplasty. We compared the groups in terms of physical function, walking ability, Japanese Knee Osteoarthritis Measure, and Life-Space Assessment. Measurements were taken before surgery and at four weeks and five months post-surgery. All patients underwent rehabilitation for five months postoperatively, first as inpatients, and then as outpatients after discharge. [Results] In the period from 4 weeks to 5 months post-surgery, physical function improved similarly in both groups in terms of muscle strength and walking ability. Despite the patients with rheumatoid arthritis being younger, their self-health assessment score by the Japanese Knee Osteoarthritis Measure and measures of life-space mobility by Life-Space Assessment were lower. [Conclusion] It is important to consider exercise therapy, and gait instruction to alleviate anxiety about health status and improve the quality of life and life-space mobility in patients with rheumatoid arthritis who undergo total knee arthroplasty.

Effects of Nordic Hamstring Exercise on Hamstring Injuries in High School Soccer Players: A Randomized Controlled Trial.

We evaluated a range of physical characteristics related to hamstring injuries, as well as the Nordic Hamstring Exercise compliance rate, and whether this influenced the rate hamstring injury. Subjects comprised 259 male soccer players from seven high schools randomly clustered into two groups, a Nordic Hamstring Exercise group and a control group. Training and match time were logged, as well as details of hamstring injury, and subsequent time lost to hamstring injury recorded over a period of 27 weeks. The Nordic Hamstring Exercise compliance rate, injury rate per 10000 playing hours and time-lost-to-sport-injury rate were calculated. The relative risk and hamstring injury severity were also calculated. The hamstring injury rate was 1.04/10 000 h in the control group and 0.88/10 000 h in the intervention group. The relative risk for hamstring injury was 1.14. The time-lost to injury rate was 1116.3/10 000 h in the control group and 113.7/10 000 h in the intervention group; with relative risk 9.81. The Nordic Hamstring Exercise in high school soccer players significantly reduced hamstring injury severity compared to a control intervention. Our results indicate that the time-lost to injury rate should be taken into account when analyzing the severity of hamstring injury.

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.

Lower-Extremity Energy Absorption During Side-Step Maneuvers in Females With Knee Valgus Alignment.

CONTEXT: Excessive knee valgus on landing can cause anterior cruciate ligament injury. Therefore, knee valgus alignment may show characteristic energy absorption patterns during landings with lateral movement that impose greater impact forces on the knee joint compared with landings in other alignments. OBJECTIVE: To investigate the energy absorption strategy in lower-extremities during side steps in females with knee valgus alignment. DESIGN: Controlled laboratory study. SETTING: University research laboratory. PARTICIPANTS: A total of 34 female college students participated in this experiment. INTERVENTIONS: Participants performed single-leg drop vertical jump and side steps. All participants were divided into valgus (n = 13), neutral (n = 9), and varus (n = 12) groups according to knee position during landing in single-leg drop vertical jumps. MAIN OUTCOME MEASURES: Lower-extremity joint angles, moments, and negative works were calculated during landing in side steps, and 1-way analysis of variance and post hoc tests were used to determine between-group differences. RESULTS: Negative works of hip extensors, knee abductors, and ankle plantar flexors during landing in side steps were significantly smaller in the valgus than in the varus group; however, negative work of the knee extensors was significantly greater in the valgus group than in varus group. CONCLUSIONS: The findings of this study indicated that landing with knee valgus induced the characteristic energy absorption strategy in the lower-extremity. Knee extensors contributed more to energy absorption when landing in knee valgus than in knee varus alignment. Learning to land in knee varus alignment might reduce the impact on the knee joint by increasing the energy absorption capacities of hip extensors, knee abductors, and ankle plantar flexors.

Factors associated with low back pain in elite high school volleyball players.

[Purpose] To determine the relationship between low back pain and a range of demographic, environmental, and injury history factors to identify potential factors for the management of low back pain. [Participants and Methods] The participants were 123 elite high school male and female volleyball players. They answered an extensive questionnaire regarding demographic details, low back pain in the previous year, volleyball-specific movements, previous regional injuries, and years of volleyball experience. Questionnaire responses were analyzed. Data were analyzed using a multivariate logistic regression analysis using the presence and absence of low back pain within 1 year as the explanatory variable. [Results] Of the 123 volleyball players, 48.0% reported low back pain. The volleyball-specific movements that induced pain were diverse (e.g., spike, serve, and pass) with no common factor. The factors associated with low back pain were an ankle injury within the previous year and years of volleyball experience. [Conclusion] The associations found in this survey indicate that particular attention should be given to more experienced players with a history of ankle injury to manage low back pain in high school volleyball players.

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.

Immediate effect of application of the pressure technique to the psoas major on lumbar lordosis.

[Purpose] To demonstrate immediate alteration in lumbar lordosis and the lumbar angle in each segment after the application of the mechanical pressure technique to the psoas major muscle (PM). [Participants and Methods] In all, 34 participants were assigned to either the PM pressure technique group (n=17) or control group (n=17). Three dimensional (3D) coordinates of the 12th thoracic spinous process and lumbar spinous processes were measured with a 3D digitizer in the prone position with 15° bilateral hip extension to compare the changes in lumbar lordosis and the lumbar extension angle in each segment in both the PM pressure technique group and control group. [Results] Mann-Whitney's U test revealed no significant differences in lumbar lordosis in either group. However, the lumbar extension angle at L4 decreased significantly after the PM pressure technique compared with that before the pressure technique. Additionally, the lumbar extension angle at L4 also decreased significantly after the PM pressure technique compared with the control group. Conversely, lumbar extension angle at L1 increased significantly after the PM pressure technique compared with that before. There was no significant difference in the lumbar extension angle at L2, L3 and L5 after the PM pressure technique. [Conclusion] This study suggests that the PM pressure technique possibly attenuates PM stiffness while reducing lumbar extension in each segment.

Fatigue influences lower extremity angular velocities during a single-leg drop vertical jump.

[Purpose] Fatigue alters lower extremity landing strategies and decreases the ability to attenuate impact during landing. The purpose of this study was to reveal the influence of fatigue on dynamic alignment and joint angular velocities in the lower extremities during a single leg landing. [Subjects and Methods] The 34 female college students were randomly assigned to either the fatigue or control group. The fatigue group performed single-leg drop vertical jumps before, and after, the fatigue protocol, which was performed using a bike ergometer. Lower extremity kinematic data were acquired using a three-dimensional motion analysis system. The ratio of each variable (%), for the pre-fatigue to post-fatigue protocols, were calculated to compare differences between each group. [Results] Peak hip and knee flexion angular velocities increased significantly in the fatigue group compared with the control group. Furthermore, hip flexion angular velocity increased significantly between each group at 40 milliseconds after initial ground contact. [Conclusion] Fatigue reduced the ability to attenuate impact by increasing angular velocities in the direction of hip and knee flexion during landings. These findings indicate a requirement to evaluate movement quality over time by measuring hip and knee flexion angular velocities in landings during fatigue conditions.