Isokinetics and Exercise Science - Volume 32, issue 1

Authors: Marušič, Jan | Kozinc, Žiga | Hadžić, Vedran | Šarabon, Nejc

Article Type: Research Article

Abstract: BACKGROUND: Measurements of hip abduction (ABD) and adduction (ADD) are important in strength and conditioning as well as in clinical practice. However, there is no clear consensus on how ABD and ADD compare in strength in different populations. OBJECTIVE: The aim was to perform a quantitative synthesis of comparisons between the isometric strength of ABD and ADD in different populations. METHODS: ABD and ADD strength data were collected and pooled mean values for ABD:ADD strength ratio were calculated and expressed as standardized mean differences. Forty studies of healthy adults, 5 studies of healthy …older adults and 14 studies of adults with various musculoskeletal injuries were included in the analysis. RESULTS: Healthy (non-athletic) males, healthy older adults, and adults with hip and groin pathologies or osteoarthritis tend to have the same ADD and ABD strength; male athletes tend to have a stronger ADD compared with ABD; healthy females and adults with patellofemoral pain tend to have a stronger ABD compared with ADD. CONCLUSIONS: These results can serve as a database to help compare and interpret measurements of ADD and ABD strength ratio in different populations. Show more

Keywords: Hip strength, lower limb, muscle capacity, agonist, antagonist

DOI: 10.3233/IES-220128

Citation: Isokinetics and Exercise Science, vol. 32, no. 1, pp. 1-10, 2024

Authors: Fallon Verbruggen, Ferdia | Hank, Mikuláš | Miřátský, Petr | Malý, Tomáš | Zahálka, František

Article Type: Research Article

Abstract: BACKGROUND: Strength differences between performance levels remain unclear in female football. Furthermore, the relationship between fulltime training and strength has been unexplored despite increased professionalisation in the sport. OBJECTIVE: The aims of this research were to examine knee flexor/extensor and hip adductor/abductor strength differences between elite and sub-elite female footballers, and then determine the relationship of strength performance to age, years of football experience (FE), and years of fulltime training (FTT). METHODS: 15 elite and 15 sub-elite professional female footballers were tested. The main outcomes were concentric isokinetic knee flexor and extensor peak …moment at 60, 180, and 300 ∘ /s, and isometric hip adductor (ADD) and abductor (ABD) force. RESULTS: The elite team had higher absolute (300 ∘ /s: 47.13–49.33 Nm vs 37.33–38.93 Nm, p < 0.05) and normalised (300 ∘ /s: 0.76–0.80 Nm/kg vs 0.59–0.62 Nm/kg, p < 0.05) knee flexor values, and higher normalised ADD (5.64–5.66 N/kg vs 4.98–5.05 N/kg, p < 0.05) and ABD force (5.80–6.00 N/kg vs 5.26–5.39 N/kg, p < 0.05) , compared to the sub-elite team. Age, FE, and FTT were correlated to knee flexor values (r = 0.381–0.559, p < 0.05) . Additionally, FTT was correlated with normalised ADD and ABD force (r = 0.362–0.546, p < 0.05 ). CONCLUSION: Sub-elite female footballers may require additional knee flexor and hip strengthening in order to make the step up to the elite level. Those who are younger or have low FTT may also be recommended additional lower limb strengthening ahead of joining a fulltime training environment. Show more

Keywords: Female, soccer, muscle strength, athletes, hip, knee

DOI: 10.3233/IES-230038

Citation: Isokinetics and Exercise Science, vol. 32, no. 1, pp. 11-20, 2024

Authors: Detanico, Daniele | Ghedini Gheller, Rodrigo | Saldanha Da Silva Athayde, Marina | Lima Kons, Rafael

Article Type: Research Article

Abstract: BACKGROUND: Judo practice requires high effort from athletes, mainly focused on the upper limbs, involving the shoulder complex. OBJECTIVE: To compare the shoulder internal (IR) and external (ER) rotation peak torque and conventional ratio (ER: IR) between judo athletes from different experience levels (novice vs. advanced) and to verify the distribution of athletes according to the ER: IR ratio classification. METHODS: Thirty-nine male judo athletes were divided into two groups (advanced: 20.5 ± 2.8 years and novice: 22.1 ± 5.5 years). The athletes performed a shoulder isokinetic …protocol to measure IR and ER strength and the ER: IR ratio in novice and advanced groups. Chi-square tests were used to investigate the distribution of athletes according to the different groups of ER: IR ratio classification, and t-tests were used to compare the IR and ER peak torque and the ER: IR ratio between novice and advanced groups, with the level of significance set at 5%. RESULTS: The main results showed higher values of IR peak torque (77.3 ± 15.7 N⋅ m in advanced vs . 48.2 ± 8.4 N⋅ m in novices; p = 0.013), and a lower ER: IR conventional ratio in advanced athletes compared to novices (0.63 ± 0.1 advanced vs . 0.73± 0.2 in novice; p = 0.01). When individual values were analyzed, advanced athletes presented higher imbalance (< 0.66 ER: IR ratio) than novices (p = 0.023). CONCLUSION: Advanced athletes presented higher shoulder IR peak torque, but higher imbalance in the ER: IR ratio than novices, probably because the long-term training induced an increase in IR strength without concomitant development in ER strength. Coaches and strength and conditioning trainers should monitor shoulder rotator strength in judo athletes to avoid muscle imbalances in this region, which is frequently employed in judo training routines. Show more

Keywords: Isokinetic, ratio, torque, combat sports, imbalance

DOI: 10.3233/IES-230027

Citation: Isokinetics and Exercise Science, vol. 32, no. 1, pp. 21-27, 2024

Authors: Kizilay, Fatma | Emin Kafkas, Muhammed | Çağatay Taşkapan, Mehmet | Haydar Demirel, Ali | Radak, Zsolt

Article Type: Research Article

Abstract: BACKGROUND: Resistance exercises are widely used to enhance muscle hypertrophy. Hypertrophy occurs with effect of mechanical loading, metabolic stress, and muscle damage. The time under tension in eccentric, isometric, and concentric phases of resistance exercises can alter muscle damage and anabolic hormone responses. OBJECTIVES: The aim of the study was to reveal the effect of the time spent in the concentric and eccentric phases of the movement on muscle damage and anabolic hormone response during resistance exercise. METHODS: Ten male subjects participated in the study. A, B, C tempo protocols were created …by changing the time under tension to be 1 or 2 seconds in the eccentric and concentric phases of bench press and squat movements. In all protocols, isometric phases were 0 sec. The metronome was used to apply tempos. Blood samples were taken before each protocol, after administration, and in the 24 th , 48 th and 72 nd hours after exercise; and serum insulin, testosterone, Insuline-like Growth Factor-1 (IGF-1), Creatine Kinase (CK) and Lactate Dehydrogenase (LDH) levels were evaluated. RESULTS: Time-wise changes in CK were statistically different for all protocols (p < 0.05). CK levels in the 24 th hour of the protocol C and the 48 th hour of the protocol B were significantly higher than those in the other protocols (p < 0.05). IGF-1 and testosterone levels were significantly higher in the protocol B in the post-test, compared to the other protocols (p < 0.05). Insulin levels in the 24 t ⁢ h hour were significantly higher in the protocol B compared to those in others (p < 0.05). Time-wise changes in LDH parameters were not statistically significant in any hours (p > 0.05). CONCLUSIONS: Extending time under tension in the eccentric phase of a bout of resistance exercise appears to affect the anabolic hormone response and muscle damage. In this way, increased metabolic response and mechanical stress can induce muscle mass gain. Show more

Keywords: Concentric, eccentric, hormone, muscle damage, tempo

DOI: 10.3233/IES-220078

Citation: Isokinetics and Exercise Science, vol. 32, no. 1, pp. 29-39, 2024

Authors: Sekine, Chie | Hayashi, Haruna | Hirabayashi, Ryo | Yokota, Hirotake | Saisu, Kazusa | Takabayashi, Tomoya | Edama, Mutsuaki

Article Type: Research Article

Abstract: BACKGROUND: Lifting heavy objects can induce postural stress and low back pain. OBJECTIVE: This study aimed to examine the effect of object weight expectations on trunk muscle activity and assess trunk muscle activity in people with chronic low back pain. METHODS: Twenty-two male college students (11 healthy and 11 participants with chronic low back pain) were recruited. The procedure was performed in three settings: lifting an expected 5-kg object, lifting an unexpected 10-kg object, and lifting an expected 10-kg object. Lifting was divided into five phases, and the muscle activity in each phase …was compared between groups (chronic low back pain/control), object weight predictions, and phases. RESULTS: Compared to the control group, the chronic low back pain group had higher erector spinae muscle activity, regardless of weight or prediction, and significantly higher rectus femoris muscle activity in the early lifting phase of the expected 10-kg object (p = 0.043). Compared to when lifting the expected 10-kg object, erector spinae muscle activity was higher in the early lifting phase of the control group when lifting the unexpected 10-kg object (p = 0.016). CONCLUSIONS: Healthy individuals and individuals with chronic low back pain had different recruitment strategies for lifting objects heavier than predicted. Show more

Keywords: Lifting, trunk muscle activity, unexpected weight, low back pain, EMG

DOI: 10.3233/IES-230044

Citation: Isokinetics and Exercise Science, vol. 32, no. 1, pp. 41-48, 2024

Authors: de Holanda Santos, Laís Regina | Batista, Gabriel de Amorim | da Silva Oliveira, Felipe Augusto | Pitangui, Ana Carolina Rodarti | de Araújo, Rodrigo Cappato

Article Type: Research Article

Abstract: BACKGROUND: Scapular dyskinesis (SD) is a modification of the positioning and movement of the scapula and is associated with shoulder pain. Exercises to strengthen the shoulder and scapular muscles have been proposed as a therapeutic strategy to reduce pain and improve function. OBJECTIVE: We aimed to investigate the electromyographic activity of the periscapular and trunk muscles in individuals with shoulder pain and SD in different multi-joint exercises. METHODS: Thirty-two subjects with subacromial pain, of both sexes, with the presence or absence of SD, participated in this study. Volunteers performed five repetitions in five …exercises (Closed Row; Pronated Row; Push-up; Scapular Push-up; T-push-up). The activity of the upper trapezius, middle trapezius, lower trapezius, serratus anterior, external oblique, and rectus abdominis muscles was recorded using electromyography. RESULTS: Our results showed a decrease in the electromyographic activity of the serratus anterior and external oblique during the T-push-up exercise in individuals with shoulder pain and SD. No differences were observed between groups for the trapezius and the rectus abdominis. CONCLUSIONS: Rehabilitation programs may initially prioritize rowing and push-up exercises to strengthen periscapular muscles. More complex exercises with greater mechanical demand on the kinetic chain, such as the T-push-up, may have to be implemented in later phases. Show more

Keywords: Electromyography, exercise therapy, scapula, shoulder pain

DOI: 10.3233/IES-230040

Citation: Isokinetics and Exercise Science, vol. 32, no. 1, pp. 49-57, 2024

Authors: Materko, Wollner | dos Reis Façanha, Caio Cesar | Guedes, Gizelly Coelho | Dias, Marcela Fabiani Silva | Costa, Alisson Vieira | Belfort, Dilson Rodrigues | da Pureza, Demilto Yamaguchi | Alberto, Alvaro Adolfo Duarte

Article Type: Research Article

Abstract: BACKGROUND: A Polar heart rate monitor is a device that measures RR intervals, but has not been correlated to accurately measure the series of RR interval signals between the ECG and the Polar ® Heart Rate Monitor Interface (HRMI) Board at rest. OBJECTIVE: The aim of the study was to evaluate the temporal cross-correlations between the Polar ® HRMI Board and an ECG to measure the series of RR intervals at rest. METHODS: The sample consisted of eighteen healthy male subjects and they were instructed …to lie in the supine position at rest while breathing normally and a time window of the last 2 min was recorded to analyse RR intervals were obtained for each subject with a Polar ® HRMI Board and an ECG. Cross-correlation analysis of RR interval signals between methods and reliability was expressed by Bland and Altman analysis. RESULTS: The cross-correlation was excellent, resulting in a mean of 0.98 ± 0.01 and no lag or delay between the signals. The bias was 0.03 ± 0.08 s or 8.0% for MeanRRi from Polar ® HRMI Board and ECG, no significant difference. CONCLUSIONS: The Polar ® HRMI Board is acceptable for assessment of serial RR intervals. The results support the reliability of the Mean RR interval compared to a resting ECG. Show more

Keywords: Bland and Altman, heart rate variability, RR interval, electrocardiograph.

DOI: 10.3233/IES-230061

Citation: Isokinetics and Exercise Science, vol. 32, no. 1, pp. 59-64, 2024

Authors: Stotz, Andreas | Mason, Joel | Zech, Astrid

Article Type: Research Article

Abstract: BACKGROUND: The muscle quality index (MQI) has been proposed as a diagnostic tool to detect individuals at risk of limited physical function. OBJECTIVE: Our goal was to examine the relationship of the MQI with physical function and compare its predictive ability with other muscle parameters of strength and mass in an older population. METHODS: Sixty-eight healthy older adults (34 male, 34 female) aged between 69 and 89 years were tested for body composition, MQI, maximum isokinetic concentric KES and physical function including sit-to-stand (STS) time, normal and maximum walking speed (WS), Timed Up …and Go (TUG) and static balance. Pearson’s correlation was applied to examine the relationship between muscle parameters. Linear regression analysis including age and sex as additional covariates was performed to assess their predictive ability for physical functions. RESULTS: MQI correlated significantly with relative KES (r = 0.611, p < 0.001), total KES (r = 0.829, p < 0.001) and leg lean tissue mass (r = 0.690, p < 0.001). The MQI was not a significant predictor for any physical function (p > 0.05). STS time was a significant predictor for normal WS and TUG time (p < 0.001). Relative KES was a significant predictor for all physical functions except static balance (p < 0.001). No muscle parameter and only age was a significant predictor for static balance. Models explained 20.4%–57.3% of variances of dependent variables. CONCLUSIONS: The MQI is a useful tool to assess leg lean tissue mass and strength of the knee extensor muscles and outperforms STS time. However, STS time and relative KES are more closely related to physical function than the MQI. Show more

Keywords: Knee extensor strength, sit-to-stand, gait speed, balance, timed up and go

DOI: 10.3233/IES-230051

Citation: Isokinetics and Exercise Science, vol. 32, no. 1, pp. 65-72, 2024

Authors: Zhao, Hanye | Seo, Dasom | Okada, Junichi

Article Type: Research Article

Abstract: BACKGROUND: Muscle fatigue is nearly unavoidable during resistance exercise, yet evaluating it in such circumstances can be challenging. OBJECTIVE: This study aimed to evaluate the validity of using the rating of perceived exertion (RPE) as a measure of muscle fatigue during non-explosive bench press (BP) exercise. METHODS: Fifteen male collegiate athletes participated in three BP tasks set at 65% of their one-repetition maximum. The RPE, spectral fatigue index (SFI), and velocity loss were measured across different experimental conditions. RESULTS: Significant effects were observed across different experimental conditions for the overall …RPE, average velocity loss, and average SFI (all p < 0.001). As the lifting tasks progressed, there were significant increases in the RPE, velocity loss, and SFI (p < 0.001). Additionally, significant differences were observed between the experimental conditions in the RPE (p < 0.001), SFI (p < 0.001), and velocity loss (p < 0.01). A significantly stronger (p < 0.05) correlation was observed between the RPE and SFI (r = 0.68, df = 117, p < 0.001) than between the velocity loss and SFI (r = 0.51, df = 117, p < 0.001). CONCLUSIONS: The corresponding changes observed in the RPE, velocity loss, and SFI suggest that both the RPE and velocity loss can be used as indicators of muscle fatigue during non-explosive BP exercise. However, due to the strong correlation between the RPE and SFI, RPE is more effective for reflecting muscle fatigue in non-explosive resistance exercise settings. Regarding ease of use, the RPE is more suitable than velocity loss for assessing muscle fatigue in training scenarios. Show more

Keywords: Perceived exertion, neuromuscular fatigue, Borg scale, surface electromyography, resistance training

DOI: 10.3233/IES-230048

Citation: Isokinetics and Exercise Science, vol. 32, no. 1, pp. 73-83, 2024