Assessing the Validity of the Ergotex IMU in Joint Angle Measurement: A Comparative Study with Optical Tracking Systems.

An observational, repeated measures design was used in this study to assess the validity of the Ergotex Inertial Measurement Unit (IMU) against a 3D motion capture system for measuring trunk, hip, and shoulder angles in ten healthy adult males (38.8 ± 7.3 y, bodyweight 79.2 ± 115.9 kg, body height 179.1 ± 8.1 cm). There were minimal systematic differences between the devices, with the most significant discrepancy being 1.4 degrees for the 80-degree target angle, denoting Ergotex's precision in joint angle measurements. These results were statistically significant (p < 0.001), with predominantly trivial to small effect sizes, indicating high accuracy for clinical and biomechanical applications. Bland-Altman analysis showed Limits of Agreement (LoA) approximately ±2.5 degrees across all angles and positions, with overall LoA ranging from 3.6 to -2.4 degrees, reflecting Ergotex's consistent performance. Regression analysis indicated uniform variance across measurements, with minor heteroscedastic errors producing a negligible underestimation trend of around 0.5 degrees in some instances. In conclusion, the Ergotex IMU is a reliable tool for accurate joint angle measurements. It offers a practical and cost-effective alternative to more complex systems, particularly in settings where precise measurement is essential.

Transparency as a Means to Analyse the Impact of Inertial Sensors on Users during the Occupational Ergonomic Assessment: A Systematic Review.

The literature has yielded promising data over the past decade regarding the use of inertial sensors for the analysis of occupational ergonomics. However, despite their significant advantages (e.g., portability, lightness, low cost, etc.), their widespread implementation in the actual workplace has not yet been realized, possibly due to their discomfort or potential alteration of the worker's behaviour. This systematic review has two main objectives: (i) to synthesize and evaluate studies that have employed inertial sensors in ergonomic analysis based on the RULA method; and (ii) to propose an evaluation system for the transparency of this technology to the user as a potential factor that could influence the behaviour and/or movements of the worker. A search was conducted on the Web of Science and Scopus databases. The studies were summarized and categorized based on the type of industry, objective, type and number of sensors used, body parts analysed, combination (or not) with other technologies, real or controlled environment, and transparency. A total of 17 studies were included in this review. The Xsens MVN system was the most widely used in this review, and the majority of studies were classified with a moderate level of transparency. It is noteworthy, however, that there is a limited and worrisome number of studies conducted in uncontrolled real environments.

Acute effects of different external compression with blood flow restriction on force-velocity profile during squat and bench press exercises.

The aim was to compare the acute effects of bench press (BP) and squat (SQ) exercises with blood flow restriction (BFR) (40%, 60%, 80% and 100% of the complete arterial occlusion pressure (AOP)) and without BFR (CON) on the mean propulsive (VelMED) and maximum (VelMAX) bar velocity. Fourteen healthy, physically active males (age, 23.6 ± 4.1 years; height, 1.85 ± 0.11 m; body weight 85.4 ± 4.1 kg) took part in the study. There was one set for each testing condition (CON, 40%, 60%, 80% and 100%) with 6 repetitions for BP and 6 repetitions for SQ, at 60% of 1RM, and 3 minutes of recovery between sets. The results showed statistically significant differences of the sets with 80% BFR vs. CON (mean difference [MD] = 0.035 m · s-1, p < 0.05, ES = 0.52 [1.02-0.03]) and 100% BFR sets vs. CON (MD = 0.074, p < 0.001, ES = 1.08 [1.79-0.38]) for BP. In the SQ exercise, statistically significant differences were found between 100% BFR vs. CON (DM = 0.031 m · s-1, p < 0.05), vs. 100% BFR 40% (MD = 0.04 m · s-1, p < 0.05). Trend analysis showed a statistically significant linear trend (F[1,9] = 34.9, p < 0.001, F[1,13] = 27.32, p < 0.001) for the VelMED in relation to the different levels of BFR. In conclusion, our results showed that BFR levels above ˜80% AOP (BP) and ˜100% AOP (SQ) produce a VelMED improvement at 60% 1RM.

Squat and Bench Press Force-Velocity Profiling in Male and Female Adolescent Rugby Players.

ABSTRACT: Alonso-Aubin, DA, Chulvi-Medrano, I, Cortell-Tormo, JM, Picón-Martínez, M, Rial-Rebullido, T, and Faigenbaum, AD. Squat and bench press force-velocity profiling in male and female adolescent rugby players. J Strength Cond Res 35(2S): S44-S50, 2021-Power development is critical for enhancing rugby performance because there is a close relationship between power and sport-specific skills. The aim of this study was to examine the force-velocity profiling generated by adolescent rugby players in the squat and bench press exercises and to compare sex-related differences. Subjects were 46 men (age: 14.48 ± 1.31 years; body height: 1.65 ± 0.09 m; and body mass: 58.07 ± 13.01 kg) and 41 women (age: 14.93 ± 2.76 years; body height: 1.63 ± 0.12 m; and body mass: 59.23 ± 12.66 kg) who were recruited from a national amateur rugby league team. Maximal strength, power, and velocity were assessed on the squat and bench press exercises using a Smith Machine and a linear power transducer with intensities ranging from 40 to 80% 1 repetition maximum (1RM) on the squat and 50-80% 1RM on the bench press. 1 repetition maximum squat and bench press performance were 104.26 ± 30.83 and 46.97 ± 13.59 kg, respectively, for men and 115.17 ± 41.42 and 45.85 ± 16.71 kg, respectively, for women. The maximum squat power results for men and women were 521.91 ± 298.75 and 591.26 ± 352.69 W, respectively, and the maximum bench press power results for men and women were 190.26 ± 150.54 and 326.16 ± 195.57 W, respectively. Significant sex-related differences (p < 0.001) were found on the squat exercise for maximum (40%), mean (40-50%), and time to maximum velocities (40-80%) as well as time to maximum power (80%). On the bench press exercise, significant sex-related differences (p < 0.001) were found for power and time to maximum velocity (40%-60%-70%-80%). These results may aid in the design of strength and conditioning programs for adolescent rugby players by targeting training prescriptions toward enhancing strength or velocity.

Integrative Neuromuscular Training Enhances Physical Fitness in 6- to 14-Year-Old Rugby Players.

ABSTRACT: Alonso-Aubin, DA, Picón-Martínez, M, Rebullido, TR, Faigenbaum, AD, Cortell-Tormo, JM, and Chulvi-Medrano, I. Integrative neuromuscular training enhances physical fitness in 6- to 14-year-old rugby players. J Strength Cond Res 35(8): 2263-2271, 2021-The purpose of this study was to assess the effects of an 8-week integrative neuromuscular training (INT) program on physical fitness measures in young rugby players. A sample of 138 male rugby players (age range, 6-14 years) was divided into 5 age-related groups: group 1 (G1) (n = 20; age, 7.05 ± 0.58), group 2 (G2) (n = 27; age, 8.57 ± 0.49), group 3 (G3) (n = 31; age, 11.02 ± 0.56), group 4 (G4) (n = 33; age, 13.12 ± 0.58, and group 5 (G5) (n = 27; age, 14.85 ± 1.53 and additionally into 2 game position groups: forwards (FOR) (n = 69) and backs (BAC) (n = 69). Physical fitness measures included the Functional Movement Screen (FMS), dominant and nondominant hand-to-eye coordination, sprint capacity, core muscular endurance, and lower- and upper-body power. Integrative neuromuscular training (INT) included progressive strength, coordination, and speed exercises performed twice per week for 20 minutes. Following INT, significant improvements in selected age-related groups (p < 0.01) were found in total FMS score G3 (effect size [ES] = 0.47), G4 (ES = 0.88), and G5 (ES = 0.58); dominant hand-to-eye coordination G1 (ES = 1.48), G2 (ES = 0.71), G3 (ES = 0.55), G4 (ES = 1.47), and G5 (ES = 1.15), nondominant hand-to-eye coordination G2 (ES = 0.74), G4 (ES = 1.34), and G5 (ES = 1.09); lower-body power G2 (ES = 0.44), G4 (ES = 0.39), and G5 (ES = 0.43); core muscular endurance G1 (ES = 0.82), G3 (ES = 0.68), and G4 (ES = 1.04); upper-body power G2 (ES = 0.53); and sprint capacity G4 (ES = 0.69). Significant improvements were also found between player's positions for all tests. These findings indicate that a progressive INT program can enhance functional movement abilities and selected physical fitness measures in young rugby players regardless of game position and age.

Effects of Two Different Training Periodization Models on Physical and Physiological Aspects of Elite Female Team Handball Players.

Manchado, C, Cortell-Tormo, JM, and Tortosa-Martínez, J. Effects of two different training periodization models on physical and physiological aspects of elite female team handball players. J Strength Cond Res 32(1): 280-287, 2018-The aim of this study was to compare training-induced changes in selected physiological and physical team handball performance factors after 2 training periodization models: traditional periodization (TP) vs. block periodization (BP). Eleven female team handball players who played over 2 consecutive seasons for a Spanish first league team were assessed twice per season during a training cycle. On each occasion, participants completed anthropometric, maximal strength, and lower-body power assessments. In addition, incremental tests to determine maximum oxygen uptake (V[Combining Dot Above]O2max), sprint- and sport-specific throwing velocity tests were performed. Block periodization group experienced significantly greater improvements than TP on squat jump (5.97%; p < 0.001), countermovement jump (8.76%; p = 0.011), hand-grip strength (8.22%; p = 0.029), bench press 1 repetition maximum (1RM) (5.14%; p = 0.049), 10-m sprint (-6.19%; p < 0.001), and 20-m sprint (2.95%; p = 0.008). Greater changes in BP group (p ≤ 0.05) were also found for the throwing velocities in sport-specific tests compared with the TP group. No significant difference between the groups were detected for the half-squat 1RM (p = 0.15) and the V[Combining Dot Above]O2max (p = 0.44). These findings suggest that BP may be more effective than TP for improving important physiological and physical team handball performance factors in high level female handball players.

Influence of Scapular Position on the Core Musculature Activation in the Prone Plank Exercise.

Cortell-Tormo, JM, García-Jaén, M, Chulvi-Medrano, I, Hernández-Sánchez, S, Lucas-Cuevas, ÁG, and Tortosa-Martínez, J. Influence of scapular position on the core musculature activation in the prone plank exercise. J Strength Cond Res 31(8): 2255-2262, 2017-Prone plank is a widely used exercise in core stability training. Research has shown that pelvic tilt plays an important role on the electromyographic (EMG) activation of core musculature. However, the influence of scapular position on EMG activation is currently unknown. Therefore, this study evaluated the influence of scapular position on the core muscles during a prone plank. Surface EMG of the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and erector spinae (ES) was collected in 15 participants (10 men and 5 women). Four variations of the prone plank were evaluated: scapular abduction with anterior (ABANT) and posterior (ABRET) pelvic tilt; and scapular adduction with anterior (ADANT), and posterior (ADRET) pelvic tilt. Individual muscle EMG and overall EMG for each plank exercise was analyzed. Joint positions were controlled with a 2D kinematic analysis. Ratings of perceived exertion (RPE) were also registered. The ADRET resulted in higher overall EMG activity compared with ABANT (p = 0.04) and ADANT (p = 0.04). Moreover, ADRET resulted in greater EMG activity compared with ADANT, ABANT, and ABRET for EO (p = 0.000; p = 0.000; p = 0.035), IO (p = 0.000; p = 0.000; p = 0.005), and ES (p = 0.019; p = 0.001; p = 0.014). Regarding RA, ADRET was significantly higher compared with ADANT (p = 0.002) and ABANT (p = 0.005). Finally, ADRET provoked a higher RPE compared with ABANT (p = 0.000), ABRET (p = 0.001), and ADANT (p = 0.015). These findings demonstrate the influence of the scapular and pelvic position on the EMG response of the core muscle groups analyzed in this study, and highlight the greater contribution of these muscles to the postural stabilizing demands during posterior pelvic tilt positions, particularly when the scapulae are in adduction.

Manual Resistance versus Conventional Resistance Training: Impact on Strength and Muscular Endurance in Recreationally Trained Men.

Manual resistance training (MRT) has been widely used in the field of physical therapy. It has also been used as a strength training method due to the accommodating resistance nature of this modality. The aim of the present study was to compare the effects of an 8-week MRT program on maximum strength and muscular endurance in comparison to conventional resistance training in recreationally trained men. Twenty healthy recreationally trained male subjects were recruited and divided into a MRT training group and a conventional training (CT) group. CT group performed bench press and lat pull-down exercises, and the MRT group performed similar movements with resistance provided by a personal trainer. Both groups completed similar training protocol and training load: 2 training sessions weekly for 3 sets of 8 repetitions at an intensity of 8 to 10 on the perceived exertion scale of 0-10. Initial maximum strength differences were not significant between the groups. Neither group showed significant changes in muscular strength or endurance. Despite the statistically non-significant pre- to post differences, a trend for improvement was observed and effect size (ES) calculations indicated greater magnitude of effects for strength and endurance changes in the MRT group in lat pulldown (g=0.84) compared to CT group. Effectiveness of MRT is similar to CT for improving muscular strength and endurance. MRT can be used as a supplemental or alternative strength training modality for recreationally trained subjects, or be considered by personal trainers especially in low equipped facility conditions.

Concurrent Validity of the Ergotex Device for Measuring Low Back Posture.

Highlighting the crucial role of monitoring and quantifying lumbopelvic rhythm for spinal curvature, the Ergotex IMU, a portable, lightweight, cost-effective, and energy-efficient technology, has been specifically designed for the pelvic and lumbar area. This study investigates the concurrent validity of the Ergotex device in measuring sagittal pelvic tilt angle. We utilized an observational, repeated measures design with healthy adult males (mean age: 39.3 ± 7.6 y, body mass: 82.2 ± 13.0 kg, body height: 179 ± 8 cm), comparing Ergotex with a 3D optical tracking system. Participants performed pelvic tilt movements in anterior, neutral, and posterior conditions. Statistical analysis included paired samples t-tests, Bland-Altman plots, and regression analysis. The findings show minimal systematic error (0.08° overall) and high agreement between the Ergotex and optical tracking, with most data points falling within limits of agreement of Bland-Altman plots (around ±2°). Significant differences were observed only in the anterior condition (0.35°, p < 0.05), with trivial effect sizes (ES = 0.08), indicating that these differences may not be clinically meaningful. The high Pearson's correlation coefficients across conditions underscore a robust linear relationship between devices (r > 0.9 for all conditions). Regression analysis showed a standard error of estimate (SEE) of 1.1° with small effect (standardized SEE < 0.26 for all conditions), meaning that the expected average deviation from the true value is around 1°. These findings validate the Ergotex as an effective, portable, and cost-efficient tool for assessing sagittal pelvic tilt, with practical implications in clinical and sports settings where traditional methods might be impractical or costly.

Effects of Blood flow Restriction and Load on Mean Propulsive Velocity and Subjective Perceived Exertion During Squat and Bench Press Exercises.

BACKGROUND: The aim of this study was to determine the influence of different percentages of blood flow restriction (BFR) and loads on mean propulsive velocity (MPV) and subjective perceived exertion during squat (SQ) and bench press (BP) exercises. HYPOTHESIS: Higher percentages of BFR will positively affect dependent variables, increasing MPV and reducing perceived exertion. STUDY DESIGN: Cross-sectional study. LEVEL OF EVIDENCE: Level 3. METHODS: Eight healthy young male athletes took part. Two sets of 6 repetitions at 70% 1-repetition maximum (1RM), 2 sets of 4 repetitions at 80% 1RM, and 2 sets of 2 repetitions at 90% 1RM were performed randomly; 5-minute recoveries were applied in all sets. The varying arterial occlusion pressure (AOP) applied randomly was 0% (Control [CON]), 80%, and 100%. RESULTS: No statistically significant differences in MPV were found during the BP exercise at any percentage of BFR at any percentage 1RM. During the SQ exercise, MPV results showed statistically significant increases of 5.46% (P = 0.04; ηp2 = 0.31) between CON and 100% AOP at 90% 1RM. The perceived exertion results for the BP exercise showed statistically significant reductions of -8.66% (P < 0.01; ηp2 = 0.06) between CON and 100% AOP at 90% 1RM. During the SQ exercise, the perceived exertion results showed significant reductions of -10.04% (P = 0.04; ηp2 = 0.40) between CON and 100% AOP at 80% 1RM; -5.47% (P = 0.02; ηp2 = 0.48) between CON and 80% AOP at 90% 1RM; and -11.83% (P < 0.01; ηp2 = 0.66) between CON and 100% AOP at 90% 1RM. CONCLUSION: BFR percentages ~100% AOP at 90% 1RM improved acutely MPV (only in SQ exercises) and reduced acutely perceived exertion (in both exercises). These findings are important to consider when prescribing resistance training for healthy male athletes.

Analysis of movement patterns by elite male players of beach volleyball.

The aim of this study was to analyse and compare movement pattems and direction of locomotion in professional men's beach volleyball. A quantitative analysis of beach volleyball play was carried out for 10 players in the European Beach Volleyball Championship 2005. Video recordings were made of the 1,997 movements in 4 matches. Analysis showed that male players used more offensive than defensive movement patterns. Defensive movement patterns were more blocks and defense than receptions. Offensive movement patterns were more attack and placements than attack preparation moves. Advance was the direction of locomotion most used. Identifying and understanding such movement patterns are vital to defining specific, effective training strategies for men's beach volleyball players.

Effects of a Teaching Personal and Social Responsibility Model Intervention in Competitive Youth Sport.

The aim of this study was to implement the teaching personal and social responsibility (TPSR) model in a competitive context analyzing the differences between the intervention and the control group on personal and social responsibility, prosocial behaviors, and self-efficacy in youth soccer players. Participants were 34 youth soccer players between the ages of 14 and 16 years old (15.18 ± 0.72) divided into two different soccer teams of 17 members, corresponding to the control and intervention groups. The implementation of the TPSR model took place during 9 months, including initial and ongoing coach training (3 months), program implementation (three sessions per week lasting 90 min during 6 months), and a series of expert-led seminars for athletes (one session per week lasting 90 min during 4 months). The questionnaires used to collect data were the Personal and Social Responsibility Questionnaire, Prosocial Behavior Scale, and two Children's Self-efficacy Scales. Results indicated that the TPSR intervention group obtained an increase in post-test levels of personal and social responsibility, prosocial behavior, and self-efficacy due to the application of the TPSR model compared with control group that used a conventional sport teaching methodology. The conclusion is that the TPSR model has the potential to be adapted and implemented with flexibility in youth sport competition contexts in order to improve personal and social responsibility, prosocial behavior, and self-efficacy.

The Benefits of Physical Exercise on Mental Disorders and Quality of Life in Substance Use Disorders Patients. Systematic Review and Meta-Analysis.

Physical exercise seems to have a promising effect on numerous variables related to the recovery of drug-dependent patients. However, some contradictions are found in the literature. The aim of this study was to perform a systematic review and meta-analysis in order to identify the effect of physical exercise on mental disorders, quality of life, abstinence, and craving, and make a comparison of the effect of exercise depending on the type of program. A search for articles was conducted using PubMed, Web of Science, and Scopus databases. Studies were selected that measured the acute effects or long-term effect (≥2 weeks) of exercise in patients who met criteria for alcohol use disorders or substance use disorders. A total of 59 studies were included. An effect of exercise on quality of life and mental disorders was identified. Subgroup analysis revealed an effect of exercise on stress (SMD = 1.11 (CI: 0.31, 1.91); z = 2.73; p = 0.006), anxiety (SMD = 0.50 (CI: 0.16, 0.84); z = 2.88; p = 0.004) and depression (SMD = 0.63 (CI: 0.34, 0.92); z = 4.31; p < 0.0001), and an effect of exercise on the eight variables included in the SF36 test. The results also showed a trend towards a positive effect on craving (SMD = 0.89 (CI: −0.05, 1.82); z = 1.85, p = 0.06). Body-mind activities and programs based on improving physical conditions produced similar results in mental disorders and quality of life. Available evidence indicates that physical exercise, both body-mind and physical fitness programs, can be effective in improving mental disorders, craving, and quality of life in drug-dependent patients.

Correction: Giménez-Meseguer, J., Tortosa-Martínez, J., Cortell-Tormo, J. M. The Benefits of Physical Exercise on Mental Disorders and Quality of Life in Substance Use Disorders Patients. Systematic Review and Meta-Analysis. International Journal of Environment Research and Public Health. 2020, 17, 3680.

The authors wish to make the following corrections to this paper [...].

Lumbatex: A Wearable Monitoring System Based on Inertial Sensors to Measure and Control the Lumbar Spine Motion.

Measuring the curvature of the lumbar spine is an important challenge in disciplines related to physical therapy, rehabilitation, and sports medicine seeking to solve the incidence of the low back pain and other spinal disorders in the population. In clinical practice, most of the methods used are manual or depend on the trained eye of the specialist who is measuring. We have developed Lumbatex: an integrated system based on inertial sensors integrated into a wearable textile device. This device is connected via Bluetooth to software, which interprets data from the sensors and provides real-time biofeedback to users in a graphical way and also a quantitative measure of the curvature and spinal motion. The system is tested in two ways: first, checking the accuracy detecting changes in curvatures; second, evaluating the usability and comfort from the user standpoint. The accuracy is checked through a static method getting curvature values from the device placed on curved platforms and a dynamic validation with volunteers performing different exercises. The results obtained showed a high accuracy measuring changes in curvature with an error lower than 1° in the static test and good usability and comfort according to the opinion of the volunteers.

Effects of functional resistance training on fitness and quality of life in females with chronic nonspecific low-back pain.

BACKGROUND: Exercise is important as adjuvant in the chronic low back pain (CLBP) treatment. Functional training could involve benefits for low back pain (LBP) patients. OBJECTIVE: To evaluate the effects of a 12-week period of functional resistance training on health-related quality of life (HRQOL), disability, body pain, and physical fitness in CLBP females. METHODS: Nineteen females CLBP were recruited according to Paris Task Force on Back Pain criteria. Participants were randomly assigned to an exercise group (EG); and a control group (CG). Subjects were tested at baseline and at week 12 after 24 sessions, 2 days per week. Body pain was assessed using visual analog scale (VAS), disability with Oswestry Disability Index (ODI) and HRQOL with Short Form 36 questionnaire. Physical fitness was measured using: flamingo test, back endurance test, side bridge test, abdominal curl-up tests, and 60-s squat test. RESULTS: EG showed significant improvements in physical function (10%; p< 0.05), body pain (42%; p< 0.05), vitality (31%; p< 0.05), physical component scale (15%; p< 0.05), VAS (62.5%; p< 0.01), ODI (61.3%; p< 0.05), balance (58%; p< 0.05), curl-up (83%; p< 0.01), squat (22%; p< 0.01), static back (67%; p< 0.01), and side bridge (56%; p< 0.01). CONCLUSION: Periodized functional resistance training decreased pain and disability and improved HRQOL, balance and physical fitness in females with CLBP, and can thus be used safely in this population.

Effects of Different Backpack Loads in Acceleration Transmission during Recreational Distance Walking.

It is well established nowadays the benefits that physical activity can have on the health of individuals. Walking is considered a fundamental method of movement and using a backpack is a common and economical manner of carrying load weight. Nevertheless, the shock wave produced by the impact forces when carrying a backpack can have detrimental effects on health status. Therefore, the aim of this study was to investigate differences in the accelerations placed on males and females whilst carrying different loads when walking. Twenty nine sports science students (16 males and 13 females) participated in the study under 3 different conditions: no weight, 10% and 20% body weight (BW) added in a backpack. Accelerometers were attached to the right shank and the centre of the forehead. Results showed that males have lower accelerations than females both in the head (2.62 ± 0.43G compared to 2.83 + 0.47G) and shank (1.37 ± 0.14G compared to 1.52 ± 0.15G; p<0.01). Accelerations for males and females were consistent throughout each backpack condition (p>0.05). The body acts as a natural shock absorber, reducing the amount of force that transmits through the body between the foot (impact point) and head. Anthropometric and body mass distribution differences between males and females may result in women receiving greater impact acceleration compared to men when the same load is carried.