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.

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.

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 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.

Does trampoline or hard surface jumping influence lower extremity alignment?

[Purpose] To determine whether repetitive trampoline or hard surface jumping affects lower extremity alignment on jump landing. [Subjects and Methods] Twenty healthy females participated in this study. All subjects performed a drop vertical jump before and after repeated maximum effort trampoline or hard surface jumping. A three-dimensional motion analysis system and two force plates were used to record lower extremity angles, moments, and vertical ground reaction force during drop vertical jumps. [Results] Knee extensor moment after trampoline jumping was greater than that after hard surface jumping. There were no significant differences between trials in vertical ground reaction force and lower extremity joint angles following each form of exercise. Repeated jumping on a trampoline increased peak vertical ground reaction force, hip extensor, knee extensor moments, and hip adduction angle, while decreasing hip flexion angle during drop vertical jumps. In contrast, repeated jumping on a hard surface increased peak vertical ground reaction force, ankle dorsiflexion angle, and hip extensor moment during drop vertical jumps. [Conclusion] Repeated jumping on the trampoline compared to jumping on a hard surface has different effects on lower limb kinetics and kinematics. Knowledge of these effects may be useful in designing exercise programs for different clinical presentations.

Deep abdominal muscle thickness measured under sitting conditions during different stability tasks.

[Purpose] This study was conducted to investigate ultrasonically determined changes in the thickness of the transversus abdominis and internal oblique muscles during different sitting conditions. [Subjects and Methods] Twenty healthy men volunteered to participate in this study. Four different sitting conditions including (A) sitting, (B) sitting with left hip flexion, (C) sitting with an abdominal hollowing maneuver (AHM), and (D) sitting with an AHM and left hip flexion, were used. Subjective exercise difficulty was evaluated. [Results] Transversus abdominis and internal oblique muscle thicknesses significantly differed between conditions, with significantly greater thickness between positions from (A) to (D). Stability of the surface when sitting had no effect on the muscle thickness of the transversus abdominis. By contrast, sitting on an unstable surface caused an increase in muscle thickness of the internal oblique in each condition. The subjects reported progressively increasing difficulty in performing each exercise in a stable position from (A) to (D), while the difficulty in an unstable position was significantly different between (A) and (B), and between (C) and (D). [Conclusion] Our findings suggest that task (B) on a stable surface should be chosen for maximal activation of transversus abdominis without inducing overactivation of the internal oblique muscle.

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.

Effects of cross-training on motor function and length of stay after total hip arthroplasty: A randomized controlled trial.

BACKGROUND: There is no consensus about which training methods will give better early outcomes after total hip arthroplasty (THA). OBJECTIVE: To investigate the short-term effects of cross trainer exercise on physical function and walking ability following THA. METHODS: Fifty patients who underwent THA were randomly allocated into two groups. The intervention program was started 3 days after surgery. The main physical function results were pain, hip range of motion, knee extensor strength, single-leg stance time, and walking performance test. In addition, the number of days of requiring to walk and the length of hospital stay were recorded. RESULTS: In the comparison between groups at discharge, the patients in the cross trainer group had significantly less hip pain while walking, improvement in knee extensor strength, increased single-leg stance time, as well as increased walking speed and stride length at discharge. The number of days required to walk and length of stay were also significantly lower in the intervention group. CONCLUSIONS: Conclusions: Cross trainer exercise commencing 3 days postoperatively improves physical function and walking ability after THA.

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.

Efficacy of semi-customized exercises in preventing low back pain in high school volleyball players: A randomized controlled trial.

BACKGROUND: Low back pain (LBP) is a common injury in high school volleyball players. We hypothesized that a prevention program could decrease the incidence of LBP in high school volleyball players. This study was an in-season cluster-randomized controlled trial. METHODS: We block-randomized 8 high school volleyball teams comprising 70 players aged 15 to 17 years into the intervention (4 teams, 34 players) and control (4 teams, 36 players) groups. The intervention program consisted of 9 physical function tests as well as 1 or 2 self-selected preventive exercises, including dynamic thoracic mobility, trunk stabilization exercises, and static stretching, performed during warm-up. Both groups were followed up for 4 weeks, during which the incidence of LBP was recorded. Physical function tests (back endurance; spinal and back flexibility; active or passive shoulder and trunk range of motion; ankle joint mobility; and iliopsoas, quadriceps, and hamstrings flexibility) were conducted before and after the intervention. RESULTS: The intervention group had a significantly lower incidence of LBP (8.8%) than the control group (33.3%) (relative risk, 3.78; 95% confidence interval, 1.17-12.23; P = .017, 1 - ß = 0.99). Lumbar extension accounted for nearly 70% of LBP incidences. Most players in the intervention group demonstrated improved physical function associated with the exercises. CONCLUSION: The semi-customized prevention program decreased the incidence of LBP and enhanced the physical function parameter in high school volleyball players.

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.