SQUAT

Purpose: A variation in squatting technique is using arms to actively push the bar up with the upper limbs which is common in bodybuilding. This study aimed to compare the Electromyography (EMG) activity of selected muscles during squat with and without upper limb assistance. Methods: This was a quasi-experimental study. Fifteen healthy male power lifters (using the convenience sampling method) participated in this study. Participants performed 2 sets of 5 repetitions while squatting 70% of their one-repetition maximum with and without upper limb assistance. Surface EMG signals were collected from 6 muscles using a wireless electromyography with a sampling frequency of 1200 Hz. The paired sample t test was used for statistical analyses at a significance level of P<0.05. The obtained data were analyzed using SPSS. Results: Average activity of the gluteus medius during the upward phase of squatting with upper limb assistance increased by 17.1% (P=0.017), compared to squatting without upper limb assistance. Mean activity ratio of the vastus medialis during the downward phase with upper limb assistance showed a 6% decrease (P=0.008). During the downward phase of squatting with upper limb assistance, the mean activity ratio of the vastus medialis to vastus lateralis increased by 15% (P=0.039). During the upward phase with upper limb assistance, the maximum activity of the gluteus medius increased by 22% (P=0.043). Conclusion: The activity level of the gluteus medius and the activity ratio of the vastus medialis to vastus lateralis increased as a result of squatting with upper limb assistance. This could possibly be helpful in the rehabilitation or prevention of injuries such as patellofemoral pain or iliotibial band friction syndrome. It could also have implications for training variation.

Objective The aim of this study was assessing the effect of feedback correcting exercise in front of mirror during running on frontal plane knee and pelvic kinematic and electromyography activity of some lower extremity muscles in single leg squat (SLS).
Materials & Methods The present research was a quasi-experimental study by pre-test, post-test design and control group. 23 active and healthy female subjects participated in two experimental and control groups with mean age (21.86±2.43) years. The subjects were selected from among students of physical education in Tehran University through convenient sampling method. Experimental group contained subjects with knee valgus and pelvic drop angle more than a mean plus and one standard deviation of the population in functional SLS. Muscular activity (RMS) of gluteus maximus, Gluteus medius, rectus femoris, vastus medialis, vastus lateralis, biceps femoris and semitendinosus, angle of knee valgus and pelvic drop were registered in end of SLS before and after 8 training sessions. The variables were compared between two groups with independent t statistical test and pair sample t-test was done within each groups with significant level of 0.05 The SPSS (version 16) was applied for statistical analysis.
Results Statistical analysis before training showed no significant differences in pelvic drop between two groups (P≥0.05), but knee valgus angle was significantly more than control group (P≤0.05). However, most muscle activities (MVC%) were greater in experimental group, but except biceps femoris (P≤0.05), no significant difference (P≥0.05) has been observed in two groups. Comparing pre and post test has showed no significant difference in knee valgus of experimental group, however it decreased around 2 degrees and although MVC% decreased in all muscles, just rectuse femoris has shown significant difference (P≤0.05). No significant difference has seen in control group in all variables (P≥0.05).
Conclusion Findings showed poor neuromuscular control in experimental group which has been improved to some extent after training because lower muscle activity and energy consumption in specific movement with similar kinematic indicates improvement of motor control or learning. It seems that mirror corrective exercise is responsible for learning by activating mirror neurons. Also decreasing muscular activity in movements will decrease fatigue, and since many injuries are related to fatigue, it can be stated that by decreasing fatigue, injuries probably will decrease. Although, there is some evidence that this training may cause positive changes in knee valgus and lower limb neuromuscular activity, but more researches are needed to be done in order to reach certain results.

Strength is one of the basic components biomotor that is needed in every sport field. In order to achieve optimal performance achievement, then the power should be increased  as  the  underlying  basis  of  the  formation  of  other  biomotor  components. Exercise increases muscle strength to cope with the load during exercise and the affects muscle hypertrophy. Exercise powers properly implemented will affect the quality and quantity improvement in print sportsmen. The exercise that is used to improve strength and hypertrophy leg muscle is by using weight training method exercise. This study aim to investigate the differences squat exercise and leg press in order to improve  strength  and  hypertrophy  leg  muscle  for  student  JPOK  FKIP  UNLAM Banjarbaru class 2011/2012. This type of quantitative research with quasi-experimental methods. The study design using a matching-only design. The population in this study was student JPOK FKIP UNLAM Banjarbaru class 2011/2012 which totale...

Introduction: Undulating training has been investigated in sedentary and trained adults, but less is known about the influence of undulating training in older adults. Purpose: This study aimed to evaluate body composition, strength levels, and physical fitness in response to traditional or undulating training in older adults. Methods: A controlled, double-arm trial was conducted in eighteen older adults (10 males, 8 females; 64 ± 2.1 years; 165.12 ± 7.5 cm; 72.5 ± 11.4 kg; 26.5 ± 3.2 k·gm−2) who were randomly assigned to traditional (n = 9, TT) or undulating training (n = 9, UT) for eight weeks. Dual X-ray absorptiometry was used to measure fat-free mass (FFM), fat mass (FM), and bone mineral density (BMD). Strength levels were evaluated by the handgrip strength and the one-repetition maximum in vertical chest press, rowing machine, squat, monopodal horizontal leg press, and leg extension. In addition, functional capacity was assessed using the Senior Fitness Test (SFT). Statistical...

Introduction: Undulating training has been investigated in sedentary and trained adults, but less is known about the influence of undulating training in older adults. Purpose: This study aimed to evaluate body composition, strength levels, and physical fitness in response to traditional or undulating training in older adults. Methods: A controlled, double-arm trial was conducted in eighteen older adults (10 males, 8 females; 64 ± 2.1 years; 165.12 ± 7.5 cm; 72.5 ± 11.4 kg; 26.5 ± 3.2 k·gm−2) who were randomly assigned to traditional (n = 9, TT) or undulating training (n = 9, UT) for eight weeks. Dual X-ray absorptiometry was used to measure fat-free mass (FFM), fat mass (FM), and bone mineral density (BMD). Strength levels were evaluated by the handgrip strength and the one-repetition maximum in vertical chest press, rowing machine, squat, monopodal horizontal leg press, and leg extension. In addition, functional capacity was assessed using the Senior Fitness Test (SFT). Statistical...

ABSTRACT Berriel, GP, Schons, P, Costa, RR, Oses, VHS, Fischer, G, Pantoja, PD, Kruel, LFM, and Peyré-Tartaruga, LA. Correlations between jump performance in block and attack and the performance in official games, squat jumps, and countermovement jumps of professional volleyball players. J Strength Cond Res XX(X): 000-000, 2020-The jump used in performance tests must be chosen according to the specificity. The aims of the present study were to analyze the correlations between height and reach of block and attack jumps and the effectiveness of such actions in official games and also the relationship between height and reach of attack and block jumps and the height achieved in squat jump (SJ), countermovement jump (CMJ), and CMJ with an arms swing (CMJA). Thirteen, male, professional volleyball players who competed in the Brazilian Volleyball Super League participated in this study. Evaluations of height and reach of attack and block jumps and height of SJ, CMJ, and CMJA were performed. Attack and block effectiveness were evaluated in 8 official games. Pearson&#39;s product-moment correlation coefficient was used, and the significance level was set at α ≤ 0.05. Attack jump height correlated with attack effectiveness in the games (r = 0.57; p = 0.05). Block jump height presented a very large correlation with SJ height (r = 0.82; p &lt; 0.01), and attack jump height presented a very large correlation with CMJ height (r = 0.86; p &lt; 0.01). Success in attack actions is directly associated with the athlete&#39;s ability to perform a vertical jump. Moreover, SJ, CMJ, and CMJA tests provided information of great applicability for the volleyball players&#39; needs. Because of the relevance of the results, these tests should be included in the assessment routine of professional volleyball players.

The experience of modernity has radically changed the way the social sciences comprehend and translate the past. Since the requested objective is no longer a proof of repetition and thus a lineal continuation, the new perspectives are indifferent to identify indications in order to verify the stability or to consolidate spatial correlations. Having been
a testimony of social memory, these indications now form a field of contradistinction, as the material representation of memory is open in alternative and conflicting readings and uses. This paper studies the multiply articulated and transformed space that includes and attributes different and often contrasting significances to agencies, behaviours and actions: the re-occupation of an old hospital constitutes an example of a space where the memory is being vindicated by different agencies, groups, and authorities who adopt prepositional actions in order to assert the localization, which is, in similar manner, culturally composed. The principal goal was the investigation of the subject’s experienced
practice; anticipating that the – often – invisible individual who is activated in this space would be able to narrate his own story, recall his own memories, or attribute his own meaning, revealing a relationship “from below” between the city and the memory

Purpose: Low back pain is one of the most common musculoskeletal disorders, and lifting is one
of its risk factors. The activities of lumbar muscles as the main muscles involved in lifting are
important with regard to identification of the allowable limits and the injury mechanisms as well
as the motor control aspects. This study aimed to investigate the effects of the lifting speed on the
lumbar muscles activities during the lifting of the light loads by squat method.
Methods: In this study, 27 healthy men were tested using electromyography (EMG). The data
were collected from the erector spinae and the multifidus muscles. The signal processing was
performed using MATLAB software after normalization to MVC and the statistical analysis was
performed with SPSS 16.
Results: The muscles activities at fast, medium, and slow speeds were not significantly different
(P>0.05); however, the difference between the numerical values of muscles activities at low and
high speeds were clearly visible in the diagram. The highest activity was observed in multifidus
muscles and then in erector spinae muscles.
Conclusion: The results indicated that the lifting speed does not have significant effect on the
activity of lumbar muscles during the lifting of light loads, but it should be noted that it can be a
risk factor in the long term for individuals who are lifting a lot of loads in a day.