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ObjectivesA pitching motion involves three-dimensional whole body movement. Proper pelvic and trunk rotation movement are important for the prevention of throwing injuries. Given that throwing is not a simple rotation movement, the evaluation of proper motion should reflect muscle strength as well as coordination and pitching motion characteristics. We have devised a throwing rotational assessment (TRA) as a new evaluation of the total rotation angle required for throwing. The purpose of this study was to examine the characteristics of players with throwing disorders compared to a pain-free group using TRA.Materials and methodsThe subjects consisted of 164 high school baseball pitchers who participated in a medical check. Pain-induced tests included an elbow hyperextension test and an intra-articular shoulder impingement test. Pitchers who felt pain in either test were classified into a disorder group (n=61). With the subjects in a position similar to the foot contact phase of throwing, the rotation angles of the pelvis and trunk were measured. All tests were performed in the throwing and opposite directions.ResultsThe disorder group had significantly lower average rotation angles of the pelvis and trunk in the throwing direction and the rotation angle of the trunk in the opposite direction compared to the healthy group.ConclusionTRA reflects the complex whole body rotation movement. Reductions in rotational angles as assessed in TRA may be associated with throwing disorders. TRA is a simple method that may be useful in the early detection of a throwing disorder and could be used in the systematic evaluation during a medical check, as well as during self-check in the sports field.

Aims This study aimed to investigate the relationship between changes in patellar height and clinical outcomes at a mean follow-up of 7.7 years (5 to 10) after fixed-bearing posterior-stabilized total knee arthroplasty (PS-TKA). Methods We retrospectively evaluated knee radiographs of 165 knees, which underwent fixed-bearing PS-TKA with patella resurfacing. The incidence of patella baja and changes in patellar height over a minimum of five years of follow-up were determined using Insall-Salvati ratio (ISR) measurement. We examined whether patella baja (ISR < 0.8) at final follow-up affected clinical outcomes, knee joint range of motion (ROM), and Knee Society Score (KSS). We also assessed inter- and intrarater reliability of ISR measurements and focused on the relationship between patellar height reduction beyond measurement error and clinical outcomes. Results The ISR gradually decreased over five years after TKA, and finally 33 patients (20.0%) had patella baja. Patella baja at the final follow-up was not related to passive knee ROM or KSS. Interestingly, when we divided into two groups - patella baja and patella normal-alta (ISR ≥ 0.8) - the patella baja group already had a lower patellar height before surgery, compared with the patella normal-alta group. The ISR measurement error in this study was 0.17. Both passive knee flexion and KSS were significantly decreased in the group with a decrease in ISR of ≥ 0.17 at final follow-up. Conclusion Patellar height gradually decreased over five years of follow-up after TKA. The reduction in patellar height beyond measurement error following TKA was associated with lower clinical outcomes. Cite this article: Bone Jt Open 2021;2(12):1075–1081.

Objectives Spondylolysis occurs bilaterally or unilaterally and bilateral spondylolysis increases the risk of developing isthmic spondylolisthesis. The characteristics of the lumbar lordosis angle (LLA), sacral slope angle (SSA), and spondylolysis fracture angle (SFA) in bilateral spondylolysis compared with those in unilateral spondylolysis have not been clarified. The purpose of this study was to compare the LLA, SSA, and SFA of bilateral and unilateral spondylolysis. Materials and methods Thirty-eight patients with lumbar spondylolysis who visited our clinic for an initial visit and 15 age-matched patients with a chief complaint of low back pain were included as controls. Computed tomography films were used to classify all spondylolysis patients into two groups: those with bilateral fractures (bilateral) and those with unilateral fractures (unilateral). The LLA and SSA were measured using lateral X-ray films and the SFA was measured using computed tomography films. Results The LLA was significantly higher in all spondylolysis patients than in the control group (p = .026). There was no significant difference in SSA between the spondylolysis and control groups (p = .28). The LLA was significantly higher in the bilateral group than in the unilateral group (p = .018). There was no significant difference in SSA between the bilateral and unilateral groups (p = .15). The SFA was significantly lower in the bilateral group than in the unilateral group (p = .024). Conclusions This study suggests that physical therapy for spondylolysis may be considered bilaterally and unilaterally.

Watanabe, Y, Yamada, Y, Yoshida, T, Matsui, T, Seo, K, Azuma, Y, Hiramoto, M, Miura, Y, Fukushima, H, Shimazu, A, Eto, T, Saotome, H, Kida, N, and Morihara, T. Relationship between physical fitness at the end of preseason and the inseason game performance in Japanese female professional baseball players. J Strength Cond Res 33(6): 1580-1588, 2019-This study examined anthropometric and fitness profiles of Japanese female professional baseball players and investigated the relationship between players' physical fitness and inseason game performance. Fifty-seven players who were registered in the Japan Women's Baseball League (JWBL) participated. Height, body mass, grip strength, back strength, knee extension and flexion strength, hamstring extensibility, vertical jump height, and horizontal jump distance were measured at preseason (February and March) in 2013. Game performance during the 2013 season (March-November) was obtained from official JWBL statistics. Vertical jump height showed significant positive correlations with individual performance records (e.g., total bases [r = 0.551], slugging percentage [r = 0.459], and stolen bases [r = 0.442]). Similar relationships were observed between horizontal jump distance and performance statistics in most cases. By contrast, grip, back, and lower-limb strength, as well as hamstring extensibility were not significantly correlated with game performance. Stepwise regression analysis selected vertical jump height as an independent variable, significantly correlating with several game performance measures (e.g., total bases: adjusted R = 0.257). Also, vertical jump height and body mass index were identified as independent variables significantly associated with stolen bases (adjusted R = 0.251). Maximal jump performance, rather than simple isometric muscle strength or flexibility, is a good performance test that can be used at the end of preseason to predict inseason batting and stolen base performance. Our findings demonstrate the importance of constructing preseason training programs to enhance lower-limb muscular power that is linked to successful inseason performance in female baseball players.

The purpose of this study was to assess the range of motions of the upper and the lower limbs in junior and senior high school baseball players to examine relationships between the range of motions and shoulder injuries caused during throwing motions. Significant differences in the range of motion were not shown for any of the items between the injured and the healthy groups of junior or senior high school students. The height, weight, age, years of baseball experience, and the age of starting baseball indicated a significant difference only for the weight in the injured junior high school group (p

Purpose: The purpose of this study was to investigate the relationship between the standing trunk extension angle and medial elbow injuries. Subjects and methods: The study participants were 90 male baseball pitchers (10–12 years) belonging to youth baseball teams. Pitching elbow injuries were evaluated by an orthopedic surgeon using ultrasound scans and physical examination findings. A single optical three-dimensional motion analysis system was used for the trunk extension measurements, with three-dimensional coordinates captured. The overall, upper, and lower trunk angles were then analyzed. Results: Trunk extension angle during standing trunk extension was significantly smaller among participants who were positive for medial elbow injuries on ultrasound scans (positive: 71.4° ± 10.3°; negative: 75.7° ± 9.2°; t = 2.05, p < 0.05). The upper trunk extension angle was significantly smaller than the lower trunk extension angle among participants who were positive for medial elbow injuries on physical examination (upper: 33.0° ± 6.9°; lower: 41.2° ± 8.2°; t = −2.42, p < 0.05). Conclusions: Trunk extension angle during standing trunk extension is associated with medial elbow injuries. Evaluating the trunk extension angle as multiple segments rather than a single rigid body is valuable.

The purpose of this study was to measure range of motion among professional women baseball players and to identify specific attributes through comparison against university men players. Subjects were 53 professional women baseball players (average age 21.9 ± 2.9 years) and 23 university men baseball players (19.8 ± 0.8 years). Measurement of shoulder external and internal rotation, neck and thoracolumbar rotation, hip internal and external rotation, SLR and HBD revealed sex differences and laterality. Women players had higher lower limb flexibility values compared with men, and like men, demonstrated laterality in range of motion in the limbs and trunk. Findings from this study may provide reference values that can be applied to women’s conditioning programs.

Objective The rotational range of motion (ROM) in the upper extremities, trunk, and lower extremities is important for throwing motion. However, unlike for the shoulders, the differences relating to age and throwing-side in trunk and lower extremity ROMs in baseball pitchers are unknown. This study examined the effects of age and dominance on the ROMs of the trunk and upper and lower extremities. Methods The study included 356 young baseball pitchers aged 9-17 years who participated in off-season baseball camps. The subjects comprised 155 youth pitchers (aged 9-14 years) and 201 high-school pitchers (aged 15-17 years) who were able to throw at full force without pain. The neck, shoulder, trunk, and hip rotational ROMs on the dominant and non-dominant side were measured by well-trained physical therapists. The differences between throwing sides and between age groups were examined using two-way analysis of variance. Results Shoulder external rotation on the dominant side was greater than that on the non-dominant side. Shoulder external and internal rotational ROMs were maintained regardless of age, whereas the trunk rotational ROM significantly increased with age. Conclusions The effects of age and dominance on ROMs of the neck, trunk, and upper and lower extremities in Japanese youth and high-school baseball pitchers were clarified. These data could be used as a specific reference and as target values for the rehabilitation of throwing injuries in young athletes.

Publisher Summary Studying refractory periods, occlusion, and inhibition using somatosensory-evoked potentials (SEPs) could explore the complex mechanisms of these synaptic connections. This chapter presents a series of SEP experiments started from the anecdotal observation that the amplitude of common peroneal nerve (CPN)-SEP was smaller than that of the posterior tibial nerve (PTN)-SEP or sural (SN)-SEP. This was contrary to the “intuitive” expectation that CPN-SEP with stimulation at the knee would produce larger amplitude response than PTN stimulation at the ankle, because CPN stimulation at the popliteal fossa activates larger fibers receiving greater peripheral receptors than the PTN stimulation at the ankle. The chapter examines the interactions of mixed nerve (PTN) and sensory nerve (SN), and also sensory (SN) and sensory (saphenous) nerves.