Isokinetics and Exercise Science - Volume 32, issue 4

Authors: Salazar-Martínez, Eduardo | Naranjo-Orellana, José | Sarabia-Cachadiña, Elena

Article Type: Research Article

Abstract: BACKGROUND: Heart Rate Variability (HRV) is a non-invasive method of assessing the autonomic nervous system response during exercise and fatigue. OBJECTIVE: The aim of the study was to analyze the validity and feasibility of the stress score index (SS) calculated from SDNN values during exercise. METHODS: 18 Men performed 2 running tests: 1) incremental exercise test; 2) 10-minute constant load test. Subjects underwent HRV analysis during the constant load test, before both tests, and afterward in a seated position at 3 intervals (0’–5’, 5’–10’, 10’–15’). The relationship between SDNN and SD2 was analyzed …before, during, and after the test. SS was calculated as 1/SD2*1000. The Bland-Altman test analyzed the reliability of ESS. The bias, limits of agreement (LoA), standard deviation of difference, intraclass correlation (ICC), and person coefficient were calculated. RESULTS: The bias was 0.15 ± 2.54 (UperLOA: 2.54; LowerLOA: - 2.23). In all conditions, SD2 and SDNN showed a positive linear relationship (r 2 = 0.986); SS and ESS were correlated; and SS and ESS described a positive linear relationship (r 2 = 0.993). CONCLUSIONS: The SS index calculation from SDNN is a reliable alternative during exercise. Show more

Keywords: HRV, fatigue, stress index, Poincaré plot, SD2

DOI: 10.3233/IES-230088

Citation: Isokinetics and Exercise Science, vol. 32, no. 4, pp. 301-307, 2024

Authors: Yoshida, Kazushi | Katsuya, Mikuto | Takano, Shogo | Hayashi, Kazuma | Hakozaki, Taisei | Shinohara, Junji

Article Type: Research Article

Abstract: BACKGROUND: Assessing intrinsic foot muscles (IFM) is important for understanding their role in loading movements. Additionally, knowledge of the impact of IFM following toe flexor muscle fatigue may aid the teaching of IFM exercises. OBJECTIVE: To examine the influence of toe flexor muscle fatigue on IFM stiffness using ultrasound shear-wave elastography. METHODS: This study included 19 college students. IFM stiffness at 10%, 50%, and 90% body weight was measured using ultrasound-based shear-wave elastography. IFM including the abductor hallucis (AbH), flexor hallucis brevis (FHB), flexor digitorum brevis (FDB), and quadratus plantae (QP) were assessed. …The fatigue induction protocol comprised a series of toe flexions at a controlled pace of 40 beats per minute and an amplitude of 75% of the maximum toe flexor strength for a duration of 5 minutes. RESULTS: Muscle stiffness significantly increased with increasing load. Toe flexor muscle fatigue significantly increased the stiffness of the FDB. CONCLUSIONS: IFM stiffness significantly increased with increasing load, and the stiffness of FDB significantly increased in the toe flexor muscle fatigue condition at DLS and SLS loads. The findings of this study will contribute to the study and clinical setting of IFM exercises. Show more

Keywords: Intrinsic foot muscles stiffness, toe flexor muscle, body weight load

DOI: 10.3233/IES-240009

Citation: Isokinetics and Exercise Science, vol. 32, no. 4, pp. 309-313, 2024

Authors: Kocakılıç, Büşra | Çil, Elif Tuğçe

Article Type: Research Article

Abstract: BACKGROUND AND PURPOSE: Football players often use quick change of direction, sudden acceleration and explosive movements. This is why chronic ankle instability is one of the most common conditions affecting this athlete population. This study investigates the effects of neuro-vestibular-ocular exercises and myofascial release on proprioception and performance in football players with chronic ankle instability. MATERIALS AND METHODS: This randomized controlled clinical trial included 60 football players aged 18–30. The players were randomly divided into two groups. The first group (NVOEG, n = 30) was included in the Neuro-Vestibular-ocular exercise training program, …while the myofascial release was applied to the second group (MRHOG, n = 30). Both protocols were applied for eight weeks. The participants’ Cumberland Ankle Instability Tool (CAIT) scores were assessed before and after the intervention. Proprioception was evaluated by using the joint position sense test. Additionally, kick speed (KS), 30-m sprint, zig-zag agility test (ZAT) and Landing error score system (LESS) tests were applied to evaluate their performance. RESULTS: Post-rehabilitation scores showed significant differences in proprioception and performance parameters compared to pre-scores in both groups. (p<0.05). Significant differences were observed between the NVOEG and MRHOG in the post-test scores, including CAIT for unstable and stable ankle, proprioception for unstable ankle, LESS, ZAT with ball performance, and 30-meter sprint test. CONCLUSIONS: The neuro-vulvular-ocular exercise training protocol had superior results in terms of proprioception and performance parameters in chronic ankle instability management for football players. Show more

Keywords: Chronic ankle instability, football, exercise, myofascial release

DOI: 10.3233/IES-240002

Citation: Isokinetics and Exercise Science, vol. 32, no. 4, pp. 315-325, 2024

Authors: Sekine, Chie | Yokota, Hirotake | Hirabayashi, Ryo | Akuzawa, Hiroshi | Ishigaki, Tomonobu | Kikumoto, Takanori | Edama, Mutsuaki

Article Type: Research Article

Abstract: BACKGROUND: Trunk muscle thickness and brightness are associated with injuries. OBJECTIVE: This study compared trunk muscle thickness and brightness between female college athletes with and without history of low back pain. METHODS: 15 sprinters, 22 volleyball-, and 18 basketball players, all females, were included. The participants were grouped based on the presence of low back pain. Short-axis ultrasound images of the rectus abdominis, external oblique, internal oblique, transverse abdominis, and lumbar multifidus were obtained. The muscle brightness was calculated after selecting the region of interest for each muscle. Muscle thickness and brightness in …both groups were compared. RESULTS: In sprinters, the right lumbar multifidus thickness was significantly thinner in the low back pain group (24.66 ± 2.98 mm) than in the healthy group (28.13 ± 2.84 mm). Volleyball and basketball players showed no significant differences in muscle thickness between the two groups for any muscle type. In volleyball players, the right transverse abdominis thickness is inclined toward thinness in the low back pain group than in the healthy group, but the difference was not significant. In all sports, there were no significant differences in muscle brightness between the two groups. CONCLUSIONS: Low back pain in female college athletes may not be related to trunk muscle thickness and brightness. Show more

Keywords: Trunk, muscle, low back pain, thickness, female athlete

DOI: 10.3233/IES-230163

Citation: Isokinetics and Exercise Science, vol. 32, no. 4, pp. 327-335, 2024

Authors: Huerta Ojeda, Álvaro | Beltrán-Inostroza, Rodrigo | Yeomans-Cabrera, María-Mercedes | Torres-Banduc, Maximiliano

Article Type: Research Article

Abstract: BACKGROUND: Isometric maximal voluntary force (IMVF) is essential for individuals’ health and physical performance. Therefore, there is a need for valid and reliable devices to assess IMVF. OBJECTIVE: To determine the validity and reliability of the Valkyria Trainer Balance® portable force platform in its isometric mode. METHODS: Fifty-eight physically healthy individuals (30 men and 28 women) participated in the study. A repeated measures design was used to compare the inter-day test-retest reliability of peak force. The validity of the Valkyria Trainer Balance® force platform was determined by comparing the peak force …with the ArtOficio® force platform. The analysis consisted of the intraclass correlation coefficient (ICC), standard error of measurement (SEM), and coefficient of variation (CV). A CV ⩽ 10% and ICC ⩾ 0.80 were considered acceptable reliability, while a ⩽ 5% and ICC ⩾ 0.90 were regarded as high reliability. RESULTS: CV the peak force showed high test-retest inter-day reliability (CV = 4.3% and ICC = 0.99). When comparing both force platforms, there was a 1.1% difference between the two devices. CONCLUSIONS: The results of this study demonstrate that the Valkyria Trainer Balance® force platform is valid and reliable for assessing IMVF in physically healthy individuals. Show more

Keywords: Validation study, reproducibility of results, equipment and supplies, muscle contraction

DOI: 10.3233/IES-240022

Citation: Isokinetics and Exercise Science, vol. 32, no. 4, pp. 337-348, 2024

Authors: Liu, Ming-Che | Weng, Pei-Wei | Chien, Yu-Hsiu | Wu, Meng-Huang | Hsu, Wei-Bin | Chen, Sheng-Wei | Yang, Ming-Ta

Article Type: Research Article

Abstract: BACKGROUND: Maca extract may regulate oxidative stress and muscle damage after exhaustive endurance exercise (EEE); however, its impact on these physiological activities remains obscure. OBJECTIVE: To examine the effects of Maca extract supplementation on oxidative stress, muscle damage and aerobic capacity after EEE. METHODS: Twenty healthy men were assigned to Maca or placebo groups and received two doses per day for 12 weeks. Pre- and post-EEE tests assessed levels of oxidative stress and muscle damage. The EEE test also recorded metrics such as time to exhaustion, peak oxygen consumption, and maximal and average heart …rates. RESULTS: Post-exercise, there was no significant difference in oxidative stress markers between the Maca and placebo groups. However, the Maca group exhibited lower stress levels at both Post-4 and Post-24 in comparison to Post-0, while the placebo group only displayed a decrease at Post-4. Notably, Maca extract supplementation immediately increased catalase activity at Post-0. Though muscle damage markers did not significantly differ, the slope of CK elevation in the Maca group appeared lower than the Placebo group, suggesting Maca’s potential in preventing muscle damage. However, no differences were noted on aerobic capacity markers. CONCLUSIONS: Maca extract may have some beneficial effects on reducing oxidative stress and possibly muscle damage after EEE. Show more

Keywords: Antioxidants, maca extract, oxidative stress, muscle damage

DOI: 10.3233/IES-240006

Citation: Isokinetics and Exercise Science, vol. 32, no. 4, pp. 349-357, 2024

Authors: Ito, Kazuhiro | Maeshima, Etsuko | Saito, Koichi | Koshiba, Hiroya | Nakamata, Takaaki | Yamaguchi, Kazuki | Maegawa, Ryota | Hatanaka, Yasuhiko

Article Type: Research Article

Abstract: BACKGROUND: Hip flexion angle-torque may not be measured accurately due to the measurement posture. OBJECTIVE: Maximum isometric hip flexion torque was measured while excluding the effects of postural retention function and compensatory motion. METHODS: Experiment 1: Maximum isometric flexion torque of the hip joint was measured at 0∘ , 30∘ , 60∘ , 90∘ , and 105∘ in 195 participants. Experiment 2: Maximum isometric hip flexion torque of 33 participants was measured in standing and supine position at 0∘ hip flexion and in end-sitting and supine position at 105∘ . …RESULTS: Experiment 1: No interaction was observed between sex and hip angle, and hip flexion torque was minimum at 0∘ hip flexion and maximum at 105∘ hip flexion in both sexes (p < 0.01). Experiment 2: An interaction between measurement position and hip angle was observed, with maximum isometric flexion torque being greater in the supine position than in the standing position (p < 0.01). Maximum isometric hip flexion torque was greater at 105∘ than at 0∘ flexion (p < 0.01). CONCLUSIONS: Maximum isometric hip flexion torque showed greater joint angle-torque characteristics in deep flexion than in shallow flexion of the hip when excluding the effects of postural retention function and compensatory motion. Show more

Keywords: Hip flexion torque, muscle strength, joint angle-torque characteristic, hip joint, Hand-Held-Dynamometer

DOI: 10.3233/IES-240003

Citation: Isokinetics and Exercise Science, vol. 32, no. 4, pp. 359-366, 2024

Authors: Waldhelm, Andy | McElroy, Lauren | Buescher, Cameron | Barnett, Haley | Cunningham, Jessica | Richards, Jared | Schwarz, Neil

Article Type: Research Article

Abstract: BACKGROUND: Test selection during the return to sport evaluation is an important aspect of ensuring athletes are safe to return to competition. OBJECTIVE: To assess the test-retest and inter-rater reliability of two new single leg hamstring bridge tests (SLHBT) and the relationships between these new tests and isokinetic strength of the quadriceps and hamstrings. METHODS: Thirty healthy college students completed the study. Two testing sessions were held three to seven days apart. Session one, participants performed two SLHBT as well as concentric isokinetic strength tests for the hamstring and quadriceps at 60, 180 …and 300∘ /sec. The participants performed only the two SLHBT during the second session. The first SLHBT, participants performed as many repetitions as possible of the SLHBT in 30-sec, while the second test measured how quickly the participants could perform five repetitions. Intraclass Correlation Coefficients (ICC2,1) were used to assess test-retest reliability while ICC(3,1) were used to test inter-rater reliability. RESULTS: The test-retest reliability for the SLHBTs was moderate to good, with ICC(2,1) ranging from 0.68 to 0.75, while the inter-rater reliability were excellent with ICC(3,1) all above 0.98. There were significant correlations between the SLHBT and the isokinetic tests, but all correlations were low to moderate. CONCLUSION: This study found good to excellent reliability with the new SLHBT and poor to moderate correlations were noted Therefore, SLHBT may not be an alternative to test hamstring test during the RTS evaluation due to the multiple compensatory strategies athletes may have. Show more

Keywords: Return to sport, functional assessments, movement system

DOI: 10.3233/IES-230084

Citation: Isokinetics and Exercise Science, vol. 32, no. 4, pp. 367-375, 2024

Authors: Choi, Hyoungjoo | You, Joshua (Sung) H.

Article Type: Research Article

Abstract: BACKGROUND: Patellar tendinopathy (PT) is a common injury involving inadequate eccentric (ECC) knee extensor contractions during dynamic sports activities. However, any discrepancies in ECC power output between Olympic athletes with and without PT utilizing a flywheel ergometer squat remain to be determined. OBJECTIVE: To compare peak ECC power, concentric (CON) power, the ECC/CON power ratio, and performance speed in female and male athletes with and without PT, respectively. METHODS: Forty Olympic athletes with and without PT were included and analyzed for ECC power, CON power, ECC/CON power ratio, and performance speed (m/s) under …varying load conditions, with analyses separated by gender. RESULTS: The ECC power, ECC/CON power ratio, and performance speed of the PT group were significantly lower than those of the non-PT (NPT) group in both genders. ECC and CON power significantly increased with higher inertial loads in the NPT groups, whereas the speed significantly decreased as the inertial load increased in both PT and NPT groups. CONCLUSIONS: Dynamic flywheel ergometer assessments may help in the quantitative diagnosis of athletes with PT under differing dynamic squat conditions. This assessment may be used to create standardized guidelines for squat performance testing, strengthening, conditioning, and rehabilitation. Show more

Keywords: Eccentric power, dynamic strength assessment, injury prevention, jumper’s knee

DOI: 10.3233/IES-230176

Citation: Isokinetics and Exercise Science, vol. 32, no. 4, pp. 377-386, 2024