Joaquin Calatayud

Exercise intensity progression for exercises performed on unstable and stable platforms based on ankle muscle activation.

Ankle sprains are a common sports injury. The literature focuses on the application of neuromuscular training for the improvement of balance, injury prevention and rehabilitation. However, there is a dearth of knowledge about the appropriate prescription of exercises using unstable platforms and surfaces. The purpose of this study was to devise an ankle rehabilitation or training program with exercise progression based on the extent of muscle activation, employing platforms with different levels of stability and additional resistance. A descriptive study of electromyography (EMG) during ankle exercises was performed with a convenience sample of healthy subjects. Forty-four subjects completed 12 exercises performed in a random order. Exercises were performed unipedally or bipedally with or without elastic tubing as resistance on various unstable (uncontrolled multiaxial and uniaxial movement) and stable surfaces. Surface EMG from the tibialis anterior (TA), peroneus longus (PL) and soleus (SOL) were collected to quantify the amount of muscle activity. Significant differences were found between exercise conditions for PL (p<.001), TA (p=.011), and SOL (p<.001). The greatest EMG activity for all muscles occurred with an upright unipedal stance on a soft stability surface with resistance. The least EMG activity for the TA and SOL were in a seated position and for the PL in an erect bipedal position without resistance. Based on the level of ankle muscle activation, exercises for the ankle should progress from bilateral exercises on exercise balls (lowest intensity), to a unipedal position on a soft surface in combination with elastic tubing (highest intensity) in order to achieve progressively greater ankle muscle activation.

Bench press and push-up at comparable levels of muscle activity results in similar strength gains.

Abstract Calatayud, J, Borreani, S, Colado, JC, Martin, F, Tella, V, and Andersen, LL. Bench press and push-up at comparable levels of muscle activity results in similar strength gains. J Strength Cond Res 29(1): 246–253, 2015—Electromyography (EMG) exercise evaluation is commonly used to measure the intensity of muscle contraction. Although researchers assume that biomechanically comparable resistance exercises with similar high EMG levels will produce similar strength gains over the long term, no studies have actually corroborated this hypothesis. This study evaluated EMG levels during 6 repetition maximum (6RM) bench press and push-up, and subsequently performed a 5-week training period where subjects were randomly divided into 3 groups (i.e., 6RM bench press group, 6RM elastic band push-up group, or control group) to evaluate muscle strength gains. Thirty university students with advanced resistance training experience participated in the 2-part study. During the training period, exercises were performed using the same loads and variables that were used during the EMG data collection. At baseline, EMG amplitude showed no significant difference between 6RM bench press and band push-up. Significant differences among the groups were found for percent change (&Dgr;) between pretest and posttest for 6RM (p = 0.017) and for 1 repetition maximum (1RM) (p < 0.001). Six repetition maximum bench press group and 6RM elastic band push-up group improved their 1RM and 6RM (&Dgr; ranging from 13.65 to 22.21) tests significantly with similar gains, whereas control group remains unchanged. Thus, when the EMG values are comparable and the same conditions are reproduced, the aforementioned exercises can provide similar muscle strength gains.

Exercise and Ankle Sprain Injuries: A Comprehensive Review

Abstract Ankle sprains are common in team sports and sports played on courts, and often result in structural and functional alterations that lead to a greater reinjury risk. Specific exercises are often used to promote neuromuscular improvements in the prevention and rehabilitation of ankle injuries. This literature review summarizes the neuromuscular characteristics of common ankle sprains and the effectiveness of exercise as an intervention for improving neuromuscular function and preventing reinjury. Our review found that appropriate exercise prescription can increase static and dynamic balance and decrease injury recurrence. In particular, the addition of dynamic activities in the exercise program can be beneficial because of the anticipatory postural adjustments identified as a key factor in the injury mechanism.

Dose-response association between leisure time physical activity and work ability: Cross-sectional study among 3000 workers.

Introduction: Regular physical activity is important for longevity and health, but knowledge about the optimal dose of physical activity for maintaining good work ability is unknown. This study investigates the association between intensity and duration of physical activity during leisure time and work ability in relation to physical demands of the job. Methods: From the 2010 round of the Danish Work Environment Cohort Study, currently employed wage earners with physically demanding work (n = 2952) replied to questions about work, lifestyle and health. Excellent (100 points), very good (75 points), good (50 points), fair (25 points) and poor (0 points) work ability in relation to the physical demands of the job was experienced by 18%, 40%, 30%, 10% and 2% of the respondents, respectively. Results: General linear models that controlled for gender, age, physical and psychosocial work factors, lifestyle and chronic disease showed that the duration of high-intensity physical activity during leisure was positively associated with work ability, in a dose-response fashion (p < 0.001). Those performing ⩾ 5 hours of high-intensity physical activity per week had on average 8 points higher work ability than those not performing such activities. The duration of low-intensity leisure-time physical activity was not associated with work ability (p = 0.5668). Conclusions: The duration of high-intensity physical activity during leisure time is associated in a dose-response fashion with work ability, in workers with physically demanding jobs.

Muscle Activity Levels in Upper-Body Push Exercises With Different Loads and Stability Conditions

Abstract Background: Exercises that aim to stimulate muscular hypertrophy and increase neural drive to the muscle fibers should be used during rehabilitation. Thus, it is of interest to identify optimal exercises that efficiently achieve high muscle activation levels. Objective: The purpose of this study was to compare the muscle activation levels during push-up variations (ie, suspended push-ups with/without visual input on different suspension systems, and push-ups on the floor with/without additional elastic resistance) with the bench press exercise and the standing cable press exercise both performed at 50%, 70%, and 85% of the 1-repetition maximum. Methods: Young fit male university students (N = 29) performed 3 repetitions in all conditions under the same standardized procedures. Average amplitude of the electromyogram (EMG) root mean square for the rectus abdominis, external oblique, sternocostal head of the pectoralis major, anterior deltoid, long head of the triceps brachii, upper trapezius, anterior serratus, and posterior deltoid was recorded. The EMG signals were normalized to the maximum voluntary isometric contraction. The EMG data were analyzed with repeated-measures analysis of variance with a Bonferroni post hoc. Results and Conclusions: Elastic-resisted push-ups induce similar EMG stimulus in the prime movers as the bench press at high loads while also providing a greater core challenge. Suspended push-ups are a highly effective way to stimulate abdominal muscles. Pectoralis major, anterior deltoid, and anterior serratus are highly elicited during more stable pushing conditions, whereas abdominal muscles, triceps brachii, posterior deltoid, and upper trapezius are affected in the opposite manner.

Core muscle activity in a series of balance exercises with different stability conditions

Literature that provides progression models based on core muscle activity and postural manipulations is scarce. The purpose of this study was to investigate the core muscle activity in a series of balance exercises with different stability levels and additional elastic resistance. A descriptive study of electromyography (EMG) was performed with forty-four healthy subjects that completed 12 exercises in a random order. Exercises were performed unipedally or bipedally with or without elastic tubing as resistance on various unstable (uncontrolled multiaxial and uniaxial movement) and stable surfaces. Surface EMG on the lumbar multífidus spinae (LM), thoracic multífidus spinae (TM), lumbar erector spinae (LE), thoracic erector spinae (TE) and gluteus maximus (GM), on the dominant side of the body were collected to quantify the amount of muscle activity and were expressed as a % of the maximum voluntary isometric contraction (MVIC). Significant differences (p<.001) were found between exercises. The three unipedal standing exercises with additional elastic resistance generated the greatest EMG values, ranging from 19% MVIC to 30% MVIC. Postural manipulations with additional elastic resistance and/or unstable devices increase core muscle activity. An adequate exercise progression based on global core EMG could start with seated positions, progressing to bipedal standing stance (i.e., from either multiaxial or stable surface to uniaxial surface). Following this, unipedal standing positions may be performed (i.e., from either multiaxial or stable surface to uniaxial surface) and finally, elastic resistance must be added in order to increase EMG levels (i.e., from stable surface progressing to any of the used unstable surfaces).

Electromyographic comparison of elastic resistance and machine exercises for high-intensity strength training in patients with chronic stroke

OBJECTIVE To investigate whether elastic resistance training can induce comparable levels of muscle activity as conventional machine training in patients with chronic stroke. DESIGN Comparative study. SETTING Outpatient rehabilitation facility. PARTICIPANTS Stroke patients (N=18) with hemiparesis (mean age, 57 ± 8y). INTERVENTIONS Patients performed 3 consecutive repetitions at 10 repetition maximum of unilateral knee extension and flexion using elastic resistance and conventional machine training. MAIN OUTCOME MEASURES Surface electromyography was measured in vastus lateralis, vastus medialis, biceps femoris, and semitendinosus and was normalized to maximal electromyography (% of max) of the nonparetic leg. RESULTS In the paretic leg, agonist muscle activity ranged from 18% to 24% normalized electromyography (% of max) (nEMG) during knee flexion and from 32% to 40% nEMG during knee extension. For knee extension, vastus lateralis nEMG was higher during machine exercise than during elastic resistance exercise (40% [95% confidence interval {CI}, 33-47] vs 32% [95% CI, 25-39]; P=.003). In the nonparetic leg, agonist muscle activity ranged from 54% to 61% during knee flexion and from 52% to 68% during knee extension. For knee flexion semitendinosus nEMG was higher (61% [95% CI, 50-71] vs 54% [95% CI, 44-64]; P=.016) and for knee extension vastus medialis nEMG was higher (68% [95% CI, 60-76] vs 56% [95% CI, 48-64]; P<.001) during machine exercise than during elastic resistance exercise. By contrast, antagonist coactivation was significantly higher during knee flexion when performed using elastic resistance compared with the machine. Lastly, there were no differences in perceived exertion between exercise modalities. CONCLUSIONS Machine training appears to induce slightly higher levels of muscle activity in some of the investigated muscles compared to elastic resistance during lower limb strength training in patients with chronic stroke. The higher level of coactivation during knee flexion when performed using elastic resistance suggests that elastic resistance exercises are more difficult to perform. This is likely due to a higher level of movement instability.

Electromyographic comparison of conventional machine strength training versus bodyweight exercises in patients with chronic stroke

Abstract Objective: To investigate whether bodyweight exercises can induce comparable levels of muscle activity as conventional machine exercises in chronic stroke patients. Methods: Eighteen patients performed three repetitions of bilateral- and unilateral machine leg press and the bodyweight exercises chair rise and hip thrust. Surface electromyography (EMG) was recorded from 10 lower extremity muscles and normalized to maximal EMG (nEMG) of the non-paretic leg. Results: For the paretic leg, the bodyweight exercises showed comparable levels of nEMG in 6 out of 10 muscles compared with the bilateral leg press. Vastus lateralis nEMG was higher during bilateral leg press compared with hip thrust (38% [95% CI 33–42] vs. 10% [95% CI 6–15], p < 0.0001) and chair rise (38% [95% CI 33–42] vs. 27% [95% CI 22–32], p < 0.0001). Vastus medialis nEMG was higher during bilateral leg press compared with hip thrust (34% [95%CI 27–40] vs. 8% [95% CI 2–15], p < 0.0001). Unilateral leg press showed higher nEMG compared with bilateral leg press in biceps femoris (28% [95% CI 23–34] vs. 19% [95% CI 13–24], p = 0.0009), gluteus maximus (32% [95% CI 23–41] vs. 25% [95% CI 16–34], p < 0.05), and vastus medialis (42% [95% CI 36–48] vs. 34% [95% CI 27–40], p = 0.0013). Discussion: In patients with chronic stroke, bodyweight exercises activate the majority of the lower limb muscles to comparable levels as bilateral leg press performed in machine. In addition, unilateral leg press was superior to the bilateral leg press and both bodyweight exercises.

Noninvasive Determination of Anaerobic Threshold Based on the Heart Rate Deflection Point in Water Cycling.

Abstract Pinto, SS, Brasil, RM, Alberton, CL, Ferreira, HK, Bagatini, NC, Calatayud, J, and Colado, JC. Noninvasive determination of anaerobic threshold based on the heart rate deflection point in water cycling. J Strength Cond Res 30(2): 518–524, 2016—This study compared heart rate (HR), oxygen uptake (V[Combining Dot Above]O2), percentage of maximal HR (%HRmax), percentage of maximal V[Combining Dot Above]O2, and cadence (Cad) related to the anaerobic threshold (AT) during a water cycling maximal test between heart rate deflection point (HRDP) and ventilatory (VT) methods. In addition, the correlations between both methods were assessed for all variables. The test was performed by 27 men in a cycle ergometer in an aquatic environment. The protocol started at a Cad of 100 b·min−1 for 3 minutes with subsequent increments of 15 b·min−1 every 2 minutes until exhaustion. A paired two-tailed Students t-test was used to compare the variables between the HRDP and VT methods. The Pearson product-moment correlation test was used to correlate the same variables determined by the 2 methods. There was no difference in HR (166 ± 13 vs. 166 ± 13 b·min−1), V[Combining Dot Above]O2 (38.56 ± 6.26 vs. 39.18 ± 6.13 ml·kg−1·min−1), %HRmax (89.24 ± 3.84 vs. 89.52 ± 4.29%), V[Combining Dot Above]O2max (70.44 ± 7.99 vs. 71.64 ± 8.32%), and Cad (174 ± 14 b·min−1 vs. 171 ± 8 b·min−1) related to AT between the HRDP and VT methods. Moreover, significant relationships were found between the methods to determine the AT for all variables analyzed (r = 0.57–0.97). The estimation of the HRDP may be a noninvasive and easy method to determine the AT, which could be used to adapt individualized training intensities to practitioners during water cycling classes.

Test-retest reliability of the star excursion balance test in primary school children

Abstract Background: Dynamic balance has been considered a fundamental skill at all ages and is required for normal daily tasks, such as walking, running, or other sports activities. The Star Excursion Balance Test (SEBT) has been widely used in recent years to identify dynamic balance deficits and improvements and to predict the risk of lower extremity injury. However, no study has demonstrated the reliability of the SEBT in children while they are performing the test in a physical education session. Reliability is needed in all measurement tools in order to provide repeatable and consistent data. Objective: To evaluate the reliability of the SEBT in primary school students in the school setting. Methods: Twenty-four healthy children with typical development were tested twice, 2 weeks apart. The tests were conducted by the same single rater and were performed during the physical education class. The test was performed under standardized conditions during the 2 testing sessions and was performed by each subject with both limbs in the 3 directions (anterior, posteromedial, and posterolateral). Four practice trials were performed in each direction before selecting 3 additional distances reached. The best value of these 3 additional measured trials was selected. The paired t test was used to ensure the absence of any systematic bias. Intraclass correlation coefficient, standard error of measurement, 95% confidence intervals (CIs), and minimal change values were calculated to assess reliability and measurement error. Results: The paired t tests revealed no significant differences between test–rest scores. Test–retest reliability for all distances reached was moderate to good. Conclusions: Reliability values suggest that the SEBT is suitable for primary school students. However, it may be more practical and feasible during extracurricular sports participation due to the time constraints and difficulties in using the test in the school setting.