Validation of a Bat Handle Sensor for Measuring Bat Velocity, Attack Angle, and Vertical Angle

Background: Bat velocity, attack angle, and vertical angle are common variables that coaches and players want to evaluate during their baseball or softball swing. Objective: The purpose of this study was to investigate and validate a baseball bat handle sensor against motion capture using recreational baseball and softball athletes for bat velocity, attack angle, and vertical angle. Methods: This single visit cross-sectional experimental design study utilized eighteen recreational baseball and softball players (ten males and eight females, age: 20.70 ± 1.69 years, height: 170.74 ± 5.69 cm, weight: 77.97 ± 12.30 kg) were recruited. Bat velocity, attack angle, and vertical angle from the bat handle sensor and 12-camera motion capture system were collected and compared using a two-tailed paired t-test. Results: Differences were statistically significant, showing that 95% of the time, the bat handle sensor overestimated the bat velocity by 1.92 to 2.77 m/s, underestimated the attack angle by -3.46 to -1.96º, and overestimated the vertical angle by 1.64 to 3.21º, compared to the motion capture system. Conclusion: The bat velocity and vertical angle were overestimated, while the attack angle was underestimated by the bat sensor. The information presented in this study can be viable information for coaches and players when utilizing the baseball bat handle sensor technology for training, practice, or in-game situations.

Ankle-foot Orthosis With an Oil Damper Versus Nonarticulated Ankle-foot Orthosis in the Gait of Patients With Subacute Stroke: A Randomized Controlled Trial

BackgroundGait improvement in patients with stroke using ankle-foot orthosis (AFO) has been compared to the effects of non-AFO use in previous studies, but the effect of different kinds of AFOs has not been clear. When considering the effect of different kinds of AFOs on gait, the dorsiflexion and plantar flexion moment of resistance is considered a key determinant of functional effect. In this study, the effect on gait of using an AFO with an oil damper (AFO-OD), which has plantar flexion resistance but no dorsiflexion resistance, and a nonarticulated AFO, which has both dorsiflexion and plantar flexion resistance, were compared in a randomized controlled trial. MethodsForty-one patients (31 men, 10 women; mean age 58.4 ± 11.3 years) in the subacute phase of stroke were randomly allocated to two groups to undergo 2 weeks of gait training by physiotherapists while wearing an AFO-OD or a nonarticulated AFO. A motion capture system was utilized to measure shod gait without orthosis at baseline and after training with the allocated AFO. Data analysis was performed focused on the spatial and temporal parameters, ground reaction force, shank-to-vertical angle, and ankle joint kinematics and kinetics. Two-way mixed ANOVA was performed to clarify the effect of AFO use and the difference between the two AFOs. ResultsThirty-six patients completed the study (17 in the AFO-OD group and 19 in the nonarticulated AFO group). Spatial and temporal parameters and ankle joint kinematics were improved after 2 weeks in both AFO groups. Interactions were found for the range of shank-to-vertical angles in paretic single stance and ankle peak power absorption. In the AFO-OD group, both parameters improved when the participants walked with the AFO compared to the shod gait, but there was no change in the nonarticulated AFO group. Power generation was not increased in either AFO group. ConclusionsThe results of this study showed that AFO with plantar flexion resistance but without dorsiflexion resistance improved the range of the shank-to-vertical angle and ankle power absorption but not power generation in a paretic stance. (336/350 words)Trial registration: UMIN000028126 Registered 1 August 2017,https://upload.umin.ac.jp/cgi-bin/icdr/ctr_menu_form_reg.cgi?recptno=R000032197

Morphometric evaluation of nasolacrimal duct

Objectives: Obstructions are very commonly seen in nasolacrimal duct before it opens into the inferior nasal meatus. Detailed anatomical knowledge of the nasolacrimal duct is crucial for physicians to understand the etiology of the obstructions, to plan ideal management option and to reduce unexpected iatrogenic injuries during surgeries. The aim of this study was to investigate morphometric properties of the nasolacrimal duct on computed tomography images. Methods: Three-dimensional computed tomography (3D-CT) of 142 adults (65 females, 77 males) were retrospectively evaluated. Antero-posterior cranial diameter, antero-posterior and transverse diameters and vertical angle of the nasolacrimal duct, distance between distal end of the nasolacrimal duct to anterior surface of the maxilla were measured and the differences evaluated statistically between right and left sides and among females and males and among different ages. All measurements were done using Osirix-Lite version 9 software. Results: None of the morphometric parameters of the nasolacrimal duct showed significant differences between right and left sides. Antero-posterior cranium and transverse diameter of the nasolacrimal duct were longer in men than women. Conclusion: Determining to morphometric properties of the nasolacrimal canal has advantages for understanding the etiology of the NLD obstructions, deciding the ideal surgical technique and reducing to unexpected injuries during surgeries related with this region.

The Effects of Bracing on Pelvic Parameters in Adolescent Idiopathic Scoliosis

Background: This study aims to evaluate the effects of bracing on the Cobb’s angle (CA) and spinopelvic parameters in adolescent idiopathic scoliosis (AIS) patients. Methods: A total of 51 AIS patients who received bracing treatment between January 2018 and August 2019 were retrospectively analyzed. The pro-bracing and in-bracing radiographs were analyzed with regard to the spinopelvic parameters. The CA, pelvic coronal obliquity angle (PCOA), thoracolumbar kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), sagittal vertical angle (SVA) and coronal vertical angle (CVA) were measured. Results: The mean age at the initiation of bracing was 13.6 ± 1.5 years. The mean pro-bracing CA was 24.0° ± 6.3°. There were no statistically significant differences between pro-bracing and in-bracing measurements of SVA and CVA. However, there were statistically significant differences between the pro-bracing and in-bracing measurements of the CA, PCOA, TLK, LL, PT and SS. A significant correlation was observed between PT variation and TLK variation in the sagittal plane. In the coronal plane, the PCOA variation was correlated to pro-bracing PCOA. Conclusion: Bracing effects of AIS can be extended to the pelvis. The pelvis should retro-rotate correspondingly to TLK hypokyphosis on sagittal plane, whereas in coronal plane, pelvic obliquity was improved independently.

Assessment of the Shank-to-Vertical Angle While Changing Heel Heights Using a Single Inertial Measurement Unit in Individuals with Incomplete Spinal Cord Injury Wearing an Ankle-Foot-Orthosis

Previous research showed that an Inertial Measurement Unit (IMU) on the anterior side of the shank can accurately measure the Shank-to-Vertical Angle (SVA), which is a clinically-used parameter to guide tuning of ankle-foot orthoses (AFOs). However, in this context it is specifically important that differences in the SVA are detected during the tuning process, i.e., when adjusting heel height. This study investigated the validity of the SVA as measured by an IMU and its responsiveness to changes in AFO-footwear combination (AFO-FC) heel height in persons with incomplete spinal cord injury (iSCI). Additionally, the effect of heel height on knee flexion-extension angle and internal moment was evaluated. Twelve persons with an iSCI walked with their own AFO-FC in three different conditions: (1) without a heel wedge (refHH), (2) with 5 mm heel wedge (lowHH) and (3) with 10 mm heel wedge (highHH). Walking was recorded by a single IMU on the anterior side of the shank and a 3D gait analysis (3DGA) simultaneously. To estimate validity, a paired t-test and intraclass correlation coefficient (ICC) between the SVAIMU and SVA3DGA were calculated for the refHH. A repeated measures ANOVA was performed to evaluate the differences between the heel heights. A good validity with a mean difference smaller than 1 and an ICC above 0.9 was found for the SVA during midstance phase and at midstance. Significant differences between the heel heights were found for changes in SVAIMU (p = 0.036) and knee moment (p = 0.020) during the midstance phase and in SVAIMU (p = 0.042) and SVA3DGA (p = 0.006) at midstance. Post-hoc analysis revealed a significant difference between the ref and high heel height condition for the SVAIMU (p = 0.005) and knee moment (p = 0.006) during the midstance phase and for the SVAIMU (p = 0.010) and SVA3DGA (p = 0.006) at the instant of midstance. The SVA measured with an IMU is valid and responsive to changing heel heights and equivalent to the gold standard 3DGA. The knee joint angle and knee joint moment showed concomitant changes compared to SVA as a result of changing heel height.

Theoretical Aspects for Calculating the Mobilized Load during Suspension Training through a Mobile Application

Introduction: This study describes the theoretical foundations of the development of an equation that allows for the estimation of the mobilized load when training with suspension devices (type TRX®) and presents a mobile application as a means for its use. Methods: Systems of equations are proposed of which the terms depend on the angulation of the device with respect to the vertical (angle α), the relationship between the height of grip, the height of the center of mass and the weight of the subject, which are recorded from a photo. Results: Based on the photo and the subject’s standing height, the application allows the user to measure the angle α, providing the values of applied force (in N) and mobilized load in relation to the percentage of body mass, applying the calculations described in our equations. The equation also provides the estimated value of the load mobilized during a push up on the floor (68% of the subject’s body mass) and the equation for the calculation of the mobilized load when the suspension device is fixed to the feet. Conclusions: It is possible to use equations to estimate the load mobilized in each repetition during training using suspension devices and to implement this algorithm in a mobile application.