Isometric Strength Database for Muscle Maximal Voluntary Endurance Field Tests: Normative Data

Background Different field tests are used to evaluate muscle capacity, in particular maximal voluntary isometric endurance. However, although there are some normative values for a few muscle endurance tests, these do not consider the weight, height, gender, or age of individuals, which are well-known factors that influence muscle performance. Hypothesis/Purpose The purpose of this study was to investigate the test–retest reproducibility of eight field tests and establish muscle endurance norms, in a healthy population, based on their anthropometric characteristics, which could allow the optimal evaluation of the entire muscle function in a quick manner. Design Case series. Methods This study was conducted in two phases. The first phase was to check the reproducibility inter- and intra-assessor for eight isometric muscle field tests on 20 volunteer subjects aged 40.9 ± 11.6 years old (age range, 21–58 years). The second part was to establish muscle maximal voluntary isometric endurance norms according to these tests on a total of 400 healthy participants grouped by age (50 males and females in each of the age brackets, 20–29; 30–39; 40–49; 50–59 years old, for a total of 200 males and 200 females). Results The intra- and inter-assessor reproducibility tests are good for all muscle measurements (the intraclass correlation coefficients varied between 0.915 and 0.996 and the coefficient of variation between 3.6 and 11.8%). The area under the receiver operating characteristic curves demonstrates a good sensibility with values greater than 0.7 for each test. Each muscle belt presents same ratio regardless of the age and gender group. The simultaneous multiple regression analyses highlight that the anthropometric characteristics of subjects influence significantly the performance of isometric tests. Conclusion This study has permitted establishing prediction equations in a healthy population according to their anthropometric characteristics as well as agonist/antagonist ratios for eight muscle isometric field tests after demonstrating a good reproducibility of all tests.

Comparison of the Effects of Three Hangboard Strength and Endurance Training Programs on Grip Endurance in Sport Climbers

Intermittent isometric endurance of the forearm flexors is a determinant factor of sport climbing performance. However, little is known about the best method to improve grip endurance in sport climbing regarding maximal or intermittent dead-hang training methods. The aim of this study was to compare the effects of three 8-week finger training programs using dead-hangs (maximal, intermittent, and a combination) on grip endurance. Twenty-six advanced sport climbers (7c+/8a mean climbing ability) were randomly distributed among three groups: maximal dead-hangs with maximal added weight on an 18 mm edge followed by MaxHangs on minimal edge depth; intermittent dead-hangs using the minimal edge depth, and a combination of both. The grip endurance gains and effect size were 34% and 0.6, respectively, for the group following maximal dead-hang training, 45% and 1, respectively, for the group following intermittent dead-hang training, and 7% and 0.1, respectively, for the group applying the combination of both training methods. Grip endurance increased significantly after 4 weeks in the group performing intermittent dead-hangs (p = 0.004) and after 8 weeks in both groups performing intermittent dead-hangs (p = 0.002) and MaxHangs (p = 0.010). The results suggest that the intermittent dead-hangs training method seems to be more effective for grip endurance development after eight week application in advanced sport-climbers. However, both methods, maximal and intermittent dead-hangs, could be alternated for longer training periods

Effect of Sacroiliac Joint Mobilization on Lumbar Pain and Function in Patients with Chronic Non-Specific Low Back Pain

Research background. About 30% of lumbar pain is caused by sacroiliac joint disfunction (Alayat et al., 2017). The problem often becomes chronic lower back pain of about 10–23% of people around the world (Diaz-Cerrillo et al., 2017). As a result, the lumbar function and muscle endurance decrease. Research aim was to investigate sacroiliac joint mobilization effect of lumbar pain and function on patients with chronic non-specifc lumbar pain. Methods. Twenty people who felt chronic non-specifc lumbar pain and had sacroiliac joint disfunction were investigated in this research. Research methods were VAS pain scale, Measurement of lumbar range of motion and Lumbar muscle stamina tests. Results. The results of the study showed that pain decreased in the study group from score 3.31 ± 0.56 to 1.38 ± 0.39 (p < 0.05). The torso muscle dynamics and isometric endurance and torso amplitude improved (p < 0.05), comparing values before and after treatment. In the control group, the pain after treatment decreased from score 3.02 ± 0.23 to 1.27 ± 0.36 (p < 0.05). The torso muscle dynamics and isometric endurance and torso amplitude improved (p < 0.05), comparing values before and after treatment. Conclusion. The spinal stabilization exercises together with sacroiliac joint mobilization are a more effective treatment than spinal stabilization exercises alone. In addition to this, average pain level decreased, function of lumbar part of spine as well as lumbar muscle stamina increased.Keywords: sacroiliac joint mobilization, chronic non-specifc lumbar pain, functional lumbar indicators.

Lumbar Muscle Fatigue Analysis Using Sorensen Test with Different Upper Body Offload Conditions

The Sorensen test has been widely used in assessing the isometric endurance of trunk muscles. In this study, a modified Sorensen test was performed using four different upper body offload conditions (0%, 25% 50% and 75%) and surface EMG (sEMG) was used to determine fatigue characteristics in lumbar muscles. Results showed that the offloading of the upper body has a statistically significant impact on the slope of the EMG median frequency, which is representative of lumbar muscle fatigue responses. The first 25% offloading significantly decreased the fatigue response in the lumbar region. In addition, the 25% offload condition was significantly different from the 75% offload condition. However, the slopes of 25% and 50% offload conditions are not statistically different from each other and same for 50% and 75% offload conditions.