Carlos Pablos

The Progression of Paraspinal Muscle Recruitment Intensity in Localized and Global Strength Training Exercises Is Not Based on Instability Alone

OBJECTIVE To evaluate electromyographic activity of several paraspinal muscles during localized stabilizing exercises and multijoint or global stabilizing exercises. DESIGN Cross-sectional counterbalanced repeated measures. SETTING Research laboratory. PARTICIPANTS Volunteers (N=25) without low-back pain. INTERVENTION Subjects performed (1) localized stabilizing exercises (callisthenic exercises with only body weight as resistance): static lumbar extension, stable (on floor) and unstable static unipedal forward flexion, stable dynamic unipedal forward flexion, and unstable supine bridge; and (2) global stabilizing exercises (70% of maximum voluntary isometric contraction [MVIC]): dead lift and lunge. MAIN OUTCOME MEASURES Mean and maximum amplitude of the electromyographic RMS of the lumbar and thoracic multifidus spinae and erector spinae. Electromyographic signals were normalized to the MVIC achieved during a back-extension exercise. RESULTS Normalizing to the MVIC, paraspinal muscles were significantly (P<.05) most active, with mean and peak amplitudes of 88.1% and 113.4% during the dynamic stable dead lift at 70% of MVIC, respectively. The supine bridge on the unstable surface obtained the significantly lowest values of 29.03% and 30.3%, respectively. The other exercises showed intermediate values that ranged from 35.4% to 61.6%. CONCLUSION Findings from this study may be helpful to strength trainers and physical therapists in their choice of exercises for strengthening paraspinal muscles. Our results suggest that in asymptomatic young experienced subjects, the dead lift at 70% of MVIC provides higher levels of mean and peak electromyographic signals than localized stabilizing exercises and other types of global stabilizing exercises.

Deadlift Muscle Force and Activation Under Stable and Unstable Conditions

Chulvi-Medrano, I, García-Massó, X, Colado, JC, Pablos, C, Alves de Moraes, J, and Fuster, MA. Deadlift muscle force and activation under stable and unstable conditions. J Strength Cond Res 24(10): 2723-2730, 2010-The objective of this study was to compare the production of force and paraspinal muscle activity between deadlifts carried out in a standard way and with different instability devices (Bosu and T-Bow). Deadlifts involve the performance of muscle activities with dynamic and isometric characteristics. Thirty-one subjects participated voluntarily in the study. Initially, they performed an isometric test for 5 seconds in each condition. After that, they performed a set of 5 repetitions with 70% of the maximum isometric force obtained in each one of the previously evaluated conditions. During the isometric tests, records of electromyographic activity and force production were obtained, whereas during the dynamic tests, only the electromyographic activity was registered. The subjects produced more force and muscle activity on the stable surface than under the other conditions during the isometric test (p < 0.05), and the same differences in muscle activity were observed during the dynamic test (p < 0.05). These data show that the performance of deadlifts under stable conditions favors a higher production of maximum strength and muscle activity. Therefore, we conclude that the use of instability devices in deadlift training does not increase performance, nor does it provide greater activation of the paraspinal muscles, leading us to question their value in the performance of other types of exercises.

Determinants of Leisure-time Physical Activity and Future Intention to Practice in Spanish College Students

Few studies analyze determinants and patterns of physical activity among college students, so it has not been possible to carry out effective interventions to promote this practice. The aim of this study was to analyze the associations between some personal, social, and environmental determinants, practice of physical activity and future intention to practice in a sample of 639 university students (321 men and 318 women), mean age 21.43 years (+/- 2.78). Physical fitness self-perception, physical activity history, and coachs support to practice physical activity have a direct effect on the practice of physical activity and an indirect effect on future intention to practice, both in men and women. The practice of physical activity has also a direct effect on future intention to practice. Likewise, the participation in sport competitions predicts practice of physical activity and future intention in men, whereas being a member of a sports club predicts practice and future intention in women.

Perceptual-Cognitive Skills and Performance in Orienteering:

The goal was analysis of the perceptual-cognitive skills associated with sport performance in orienteering in a sample of 22 elite and 17 nonelite runners. Variables considered were memory, basic orienteering techniques, map reading, symbol knowledge, map-terrain-map identification, and spatial organisation. A computerised questionnaire was developed to measure the variables. The reliability of the test (agreement between experts) was 90%. Findings suggested that competence in performing basic orienteering techniques efficiently was a key variable differentiating between the elite and the nonelite athletes. The results are discussed in comparison with previous studies.

Effects of a rhythmic and choreographic program in obese and overweight participants

INTRODUCTION Currently there is a growing trend in the prevalence of overweight and obesity. This increased prevalence trend leads to an increase in the costs of health care. OBJECTIVE The aim of the present study was to analyze the effects on physical fitness and bone mineral density through an intervention program of physical activity based on rhythmic and choreographic activities in an overweight and obese population. METHOD An 8-month physical activity based on rhythmic and choreographic activities was conducted in overweight and obese people. Thirty-four participants aged 50.43 ± 10.57 with a body mass index (BMI) 38.37 ± 4.82 took part in the physical activity program. This study assesses the effects of fitness, percentage of body fat and bone mineral density (BMD). RESULTS After an 8-month physical activity intervention program based on rhythmic and choreographic activities, significant differences were found in: percentage of body fat (p = 0.004), aerobic capacity (p = 0.023), flexibility of the lower limbs (flexibility in the right leg p = 0.029 and left leg p = 0.002), balance (p < 0.001), strength in lower limbs (p = 0..003) and strength in upper limbs (p < 0.001). Besides that, significant differences were found in parameters related with BMD such as T-Score (p = 0.025) and Z-Score (p = 0.012), Bone Quality Index (BQI) (p = 0.026) and an increase in Broadband Ultrasound Attenuation (BUA) although not a statistically significant one (p = 0.939). CONCLUSIONS These findings suggest that a physical activity program based on rhythmic and choreographic activities can act as a preventive method of mobility and fragility, as well as preventing bone loss.

A lower-limb training program to improve balance in healthy elderly women using the T-bow device.

Abstract Ageing impairs balance, which increases the risk of falls. Fall-related injuries are a serious health problem associated with dependency and disability in the elderly and results in high costs to public health systems. This study aims to determine the effects of a training program to develop balance using a new device called the T-Bow®. A total of 28 women > 65 years were randomly assigned to an experimental group (EG) (n = 18; 69.50 [0.99] years), or a control group (CG) (n = 10; 70.70 [2.18] years). A program for lower limbs was applied for 8 weeks using 5 exercises on the T-Bow®: squat, lateral and frontal swings, lunges, and plantarflexions. The intensity of the exercises was controlled by time of exposure, support base, and ratings of perceived exertion. Clinical tests were used to evaluate variables of balance. Static balance was measured by a 1-leg balance test (unipedal stance test), dynamic balance was measured by the 8-foot-up-and-go test, and overall balance was measured using the Tinetti test. Results for the EG showed an increase of 35.2% in static balance (P < 0.005), 12.7% in dynamic balance (P < 0.005), and 5.9% in overall balance (P > 0.05). Results for the CG showed a decline of 5.79% in static balance (P > 0.05) but no change in the other balance variables. Thus the data suggest that implementing a training program using the T-Bow® could improve balance in healthy older women.

RELATION OF BODY MASS INDEX AND BODY FAT MASS FOR SPANISH UNIVERSITY STUDENTS, TAKING INTO ACCOUNT LEISURE-TIME PHYSICAL ACTIVITY

The objective of this cross-sectional study was to analyze the relation of Body Mass Index with body fat mass while taking into account the amount of leisure-time physical activity for 299 male university students. Body fat mass was measured by bioelectrical impedance analysis. An estimation of energy expenditure in leisure-time physical activity in metabolic equivalents (METs) was obtained so participants were divided into six activity groups by percentile: no physical activity by the first group and participants physically active were divided into five groups by percentiles: <25%, 26–50%, 51–75%, 76–90%, and 91–100%. Correlations of Body Mass Index with body fat mass were strong in different groups—values ranged from .76 to .85, except for the >90% group.