EMG analysis while using a smartphone

The purpose of this study was to clarify the influence of different postures on the activity of the shoulder girdle and lower back muscles while using a smartphone. Sixteen healthy male participants maintained two postures while using a smartphone : a good posture in which the tragus and acromion were closer to the vertical line passing through the greater trochanter, and a poor posture in which the tragus and acromion were farther from the vertical line passing through the greater trochanter. The target muscles were the rhomboid major (Rhom), upper trapezius, middle trapezius, lower trapezius (LT), lumbar erector spinae (LES), and lumbar multifidus (LMF). The activities of the Rhom and LT were significantly lower with poor posture than those with good posture. The activities of LES and LMF were significantly higher with poor posture than those with good posture. The results of this study indicated that poor posture was associated with hypoactivity of the shoulder girdle muscles and hyperactivity of the lower back muscles when compared with good posture. Poor posture for prolonged periods while using a smartphone would lead to malfunction of the shoulder girdle muscles and musculofascial lower back pain

EMG activity during 2000 m rowing

This study aimed to clarify the changes in the activity of the trunk and lower limb muscles during 2000-m rowing. Ten male rowers performed a 2000-m race simulation on a rowing ergometer. Electromyography results of the abdominal muscles, back muscles, gluteus maximus (GMax), biceps femoris (BF), and rectus femoris (RF) were recorded. The electromyographic activity during the three strokes after the start (initial stage), at 1000m (middle stage), and before the end (final stage) were analyzed. From the handle position, the rowing motion was divided into five phases (early-drive, middle-drive, late-drive, early-recovery, and late-recovery). The peak activities of the abdominal muscles, back muscles, GMax, and BF in each stroke of the rowing motion were delayed at the middle and final stages compared to the initial stage (P < 0.05). The peak activity of the RF was observed in the late-drive phase at the initial stage, whereas a high RF activity was observed in the middle-drive phase at the middle and final stages (P < 0.05). Considering the results of the activity of the back muscles and RF, RF muscular endurance enhancement may lead to a decrease in the load on the back muscles and help prevent muscular low back pain in rowers

movement self-screening scores and pain

Background : Various musculoskeletal screening and functional performance tests are used to evaluate physical condition. However, validated analysis tools that can identify gaps in pain knowledge during athletes’ daily training are lacking. This study aimed to investigate the relationship between pain intensity in athletes during their daily training and the KOJI AWARENESS™ test in order to determine whether body dysfunction is related to pain among athletes. Methods : This cross-sectional study was conducted in a fitness center at the authors’ affiliated institution. Thirty-five athletes (17 women and 18 men) aged 20-40 years were selected for study participation. KOJI AWARENESS™ self-evaluated test scores and pain intensity during daily training, as assessed on the numerical rating scale (NRS), were recorded. Results : The KOJI AWARENESS™ score showed a strong negative correlation with the NRS score for pain intensity during daily training (r = −0.640, P < 0.001). There was a significant negative correlation between KOJI AWARENESS™ and NRS scores, even when body mass index, sex, and age were entered as control variables. Conclusions : KOJI AWARENESS™ was highly accurate in detecting pain in athletes during their training

Effectiveness of KOJI AWARENESS tool

Background : The KOJI AWARENESS™ screening test is a self-administered screening tool for assessment of mobility, stability, and strength. It provides corrective exercises corresponding to the individual’s answers to the KOJI AWARENESS™ test questions. However, there is no evidence of the effectiveness of corrective exercises in improving KOJI AWARENESS™ screening test scores and activity-related pain. Methods : Twenty- six healthy subjects (11 female and 15 male ; age 20–50 years) were selected for participation. In a controlled laboratory setting, subjects were administered the KOJI AWARENESS™ test and were provided with individualized exercise programs based on the results of this first test. KOJI AWARENESS™ results were checked on the first day immediately after the first exercise session, and then again after the two-week program. Pain intensity was also assessed during daily training using a numerical rating scale. Results : Compared to pre-intervention, KOJI AWARENESS™ scores were significantly higher immediately after the first corrective exercise session and after 2 weeks of intervention (p < 0.001). Moreover, pain intensity was significantly lower after 2 weeks of intervention (p < 0.001). Conclusions : Individualized KOJI AWARENESS™ corrective exercises were effective immediately on the first day and also after the two-week program in improving the KOJI AWARENESS™ score and reducing pain intensity during daily training

Unilateral rotation in baseball fielder causes low back pain contralateral to the hitting side

Low back pain (LBP) often occurs in baseball players ; however, the characteristics of the location of their LBP with respect to their throwing and hitting sides have not been clarified. In order to clarify the left-right asymmetry of LBP that occurs in baseball players, we surveyed 247 university baseball players using an LBP questionnaire. The main investigational items were : throwing and hitting side, position at the time of LBP experience, and LBP location. Based upon the indication of their throwing and hitting side, subjects were classified into unilateral rotational (UR) or bilateral rotational (BR) types. Subjects were also classified into categories of LBP location as described by ipsilateral or contralateral to dominant side of throwing or hitting. Chi-square test or Fisher exact test were used to compare LBP location side by rotational type (UR/BR) in all subjects and by position (pitcher/fielder). We found that among fielders, LBP occurring contralateral to the hitting side in UR was significantly more frequent than that in BR. We conclude that LBP occurred in baseball fielders with a left-right asymmetry, which suggests that high frequency unilateral rotation causes the lumbar region contralateral to the dominant hitting side to be subject to a high load

Validity of the KOJI AWARENESS self-screening test for body movement and comparison with functional movement screening.

ObjectiveThis study aimed to validate the KOJI AWARENESS™, a self-screening movement test, and compare it with the Functional Movement Screen (FMS).MethodsFifty-seven healthy participants completed the KOJI AWARENESS™ and functional movement screening. Pearson's correlation coefficients were used to assess the validity of the test. Subsequently, partial correlation analysis was used to determine the associations between age, sex, body mass index, and sports level as control variables and motor function.ResultsCorrelation and partial correlation analyses showed a strong positive correlation between the functional movement screening and the KOJI AWARENESS™ scores.ConclusionThis study found that the KOJI AWARENESS™ test is valid and comparable to functional movement screening. It can be used for self-screening of movement

External focus instruction using a paper balloon: impact on trunk and lower extremity muscle activity in isometric single-leg stance for healthy males

IntroductionCore stability is crucial for preventing and rehabilitating lumbar spine injuries. An external focus instruction using a paper balloon is an effective way to activate the trunk muscles. However, the degree of trunk and lower extremity muscle activation during single leg stance with external focus instruction using a paper balloon is unknown. This study aimed to investigate the core muscle involving activity in the trunk and lower extremities on both the support and non-support sides with or without using external focus instruction using a paper balloon during isometric single-leg stance.MethodsThirteen healthy males aged 20–28 years volunteered to take part in this study and performed a single leg stance task with and without an external focus instruction, pressing their non-supporting foot onto a paper balloon without crushing it. The participant's muscle electrical activity was recorded during the single leg task using surface EMG and intramuscular EMG for six trunk muscles (transversus abdominis, internal oblique, external oblique, rectus abdominis, multifidus, and lumbar erector spinae) and five lower extremity muscles (gluteus maximus, gluteus medius, adductor longus, rectus femoris, and biceps femoris)ResultsCompared to the normal single leg stance, the external focus instruction task using a paper balloon showed significantly increased transversus abdominis (p &lt; 0.001, p &lt; 0.001), internal oblique (p = 0.001, p &lt; 0.001), external oblique (p = 0.002, p = 0.001), rectus abdominal (p &lt; 0.001, p &lt; 0.001), lumbar multifidus (p = 0.001, p &lt; 0.001), lumbar erector spinae (p &lt; 0.001, p = 0.001), adductor longus (p &lt; 0.001, p &lt; 0.001), rectus femoris (p &lt; 0.001, p &lt; 0.001), and biceps femoris (p &lt; 0.010, p &lt; 0.001) muscle activity on the support and non-support sides.ConclusionIn conclusion, external focus instruction using a paper balloon significantly activates the trunk and lower extremities muscles on both the support and non-support sides. This finding provides insights for designing programs to improve coordination and balance. The benefits extend to diverse individuals, encompassing athletes, tactical professionals, and the general population, mitigating the risk of injury or falls linked to inadequate lower limb balance