Purpose: We aimed to evaluate shoulder muscle activities during shoulder external rotation exercises using an elastic band with the arm at the side or at 90° of abduction in static and dynamic body positions.
Methods: In 2017, a total of 19 right-handed male subjects were included in this study. Surface electromyography signals were recorded from the anterior deltoid, middle deltoid, upper trapezius, lower trapezius, serratus anterior, and infraspinatus muscles. The subjects underwent maximal voluntary isometric contraction testing of each muscle in the W position or 90/90 position. Subjects performed the exercise in the sitting, static squat, static rotational squat, dynamic squat to standing (DSS), and dynamic squat to standing and trunk rotation (DSSR) positions.
Results: The main finding of this study was that shoulder external rotation exercises in the DSSR position were effective in reducing shoulder muscle activities except in the serratus anterior compared with static rotational squat position.
Conclusion: DSSR enabled effective control of scapular motion with less shoulder muscle activation. Therefore, the kinetic chain exercises incorporated with lower extremity, hip, or trunk would be beneficial for shoulder muscle exercises, which is required for patients with weak periscapular muscles, in whom the lower trapezius activities were found to be frequently decreased.

Purpose: The aim of current study is to verify the efficacy of extracorporeal shock wave therapy (ESWT) in neck and shoulder pain syndrome.
Methods: We enrolled 23 patients with neck and shoulder pain syndrome (mean age, 55±16 years; onset, 12.65±8.90 months) who underwent ESWT from July to December 2019. ESWT (4 to 5 bar or 0.23-0.45 mJ/mm2, 1,500 to 2,000 times/region, 7 Hz) was performed at least 4 consecutive times per week. Evaluated outcomes were visual analogue scale (VAS) of pain and tenderness, neck disability index (NDI), and shoulder passive range of motion (ROM; forward flexion [FF], external rotation at neutral [ER], internal rotation at back [IR]). Pain and tenderness VAS scores were assessed at every follow-up, while NDI and shoulder ROM were evaluated two times before treatment and at the final follw-up (at 4.52±0.73 weeks).
Results: The pain VAS score decreased from 5.5±2.4 at first visit to 4.0±1.8 (p=0.001), 3.3±2.1 (p=0.02), and 3.1±2.2 (p=0.29) at the first, second, and third follow-up visits. The tenderness VAS at first visit was 5.98±1.89, which decreased to 5.17±1.83 (p=0.005), 4.61±1.67 (p=0.05), and 4.09±1.92 (p=0.06) at the first, second, and third follow-up visits. NDI was significantly reduced from 18.04±8.86 to 10.04±6.94 at last follow-up (p=0.001) and shoulder ROM was significantly improved after treatment (FF: 159.6°±28.0° to 177.8°±8.5°, p=0.001; ER: 72.2±15.7° to 79.6±2.1°, p=0.02; IR: 10.2±3.49 [T 10] to 6.9±1.7 [T 7], p=0.001).
Conclusion: Consecutive ESWT was effective in treating neck and shoulder pain syndrome with functional improvement and pain reduction. Regarding simultaneous pain and tenderness reduction, receiving ESWT two times per week was effective.

Purpose: The purpose of this study was to investigate the effects of kartogenin (KGN) on the tendon-bone interface in a rat rotator cuff tear model.
Methods: Twenty male rats were divided into two equal groups; group 1 (repair only) and group 2 (KGN single injection). A rat rotator cuff rupture model was prepared, and KGN (500 μM) was injected into the repair site. The specimens were collected after 8 weeks, and biomechanical and histological analyses were performed. We assessed the healing quality of the tendon-to-bone repair site using six aspects of tendon tissue. The histological findings were classified semiquantitatively into four grades (grade 0, the poorest appearance; grade 1, poorer; grade 2, better; and grade 3, marked regeneration).
Results: Group 2 showed a higher mean ultimate load to failure than the control group (group 1: 25.78±31.38 N, group 2: 55.64±36.02 N; p=0.011). On histological analysis, group 2 exhibited a significantly greater total score (group 1: 7.20±2.14, group 2: 9.50±1.84; p=0.019), collagen fiber continuity (group 1: 1.20±0.42, group 2: 1.70±0.48; p=0.024), and collagen fiber density (group 1: 1.50±0.52, group 2: 2.20±0.63; p=0.080). Metachromasia were more intense in group 2 than in the control group.
Conclusion: A single injection of KGN reinforces biomechanical strength and the formation of collagen and fibrocartilage at the tendon-to-bone interface in a rat rotator cuff tear model.

Purpose: Advancements in surgical and nonsurgical care for congenital heart disease (CHD) have enabled an increase in survival into adulthood of these children with CHD, thereby contributing to the growth of the aging population, it is important to evaluate these functional outcome measures in adults with CHD. Therefore, this study aimed to compare the subjective and objective assessments of physical activity (PA) and exercise capacity (EC) in adults with CHD and age-matched, healthy controls.
Methods: Forty-six adults with CHD (male, 26; age, 20.6±1.3 years) and forty-six healthy controls (male, 24; age, 21.2±1.6 years) underwent an assessment of subjective and objective PA levels using the Global Physical Activity Questionnaire and the accelerometer device (GENEActiv) worn on the wrist for seven consecutive days, respectively. EC was directly measured by peak oxygen uptake (peak VO2) during a graded exercise test.
Results: Subjectively and objectively measured of moderate to vigorous PA in adults with CHD were lower than those with healthy controls (p=0.008, p=0.004), while the majority of adults with CHD have achieved the recommended levels of PA (150 min/wk). In addition, peak VO2 was lower in adults with CHD than in healthy controls (30.8±8 mL/kg/min vs. 46.7±10 mL/kg/min, p<0.001).
Conclusion: Although the majority of adults with CHD meet the recommended levels of PA, their overall PA levels and EC are still lower than those of age-matched, healthy adults without CHD.

A 36-year-old female amateur cyclist developed mononeuropathy of the deep branch of the ulnar nerve due to nerve compression adjacent to the ulnar tunnel (type II Guyon's canal syndrome) caused by prolonged bicycle riding. The patient's signs and symptoms persisted even after refraining from cycling for 4 weeks; thus, she underwent decompression of the deep branch of the ulnar nerve in the palm and wrist. Three months postoperation, she recovered nearly full power and function of her left hand.

This study compared muscle function pre- and post-central fatigue caused by a marathon, using maximal displacement (Dm), which indicates muscular stiffness in tensiomyography (TMG) results. Blood and noninvasive TMG test were performed on the 1st, 3rd, and 5th days before and immediately after the marathon. The muscles assessed were the vastus lateralis (VL), vastus medialis (VM), rectus femoris (RF), biceps femoris (BF), semitendinosus (ST), tibialis anterior, gastrocnemius lateralis, and gastrocnemius medialis. Lactate dehydrogenase levels (lactate dehydrogenase) increased sharply immediately after the competition and decreased to the pre-competition level after 5 days. Dm was the highest immediately post-competition at BF, ST, VL, VM, and RF muscles, with a tendency to decrease to pre-competition levels after 1 day. The application of TMG to identify muscle changes in central fatigue studies may be appropriate in the proximal region rather than in the distal region.