It has been said that personal trainers get most of the information from muscle magazines. What scares them is that they blindly apply this new (sometimes rather inaccurate) knowledge with themselves or, even worse, with their customers. Remember, do not believe everything you read ... sometimes a little knowledge can be very dangerous! Well, this time as coaches, that at least you start to consider the links listed at the end of the articles. From these often forgotten sources, much can be learned. And if they are not there, you must question its authenticity. It may take me just a few minutes to read the article, but hours to see the links! Here are some nuggets of information that may be useful to you:
Muscle strength calf in humans.
Trappe SW, Trappe TA, Lee GA, Costill DL.
Int J Sports Med 2001 Apr; 22 (3): 186-91
Laboratory of Human Achievement, Ball State University
OBJECTIVE: In order to measure the strength characteristics of the lower leg muscles, 18 subjects (14 men, 4 women, age = 34.3 ± 2.4 years) were tested using a specially designed torque device (TVD). This TVD is a hardware interface with the subject's lower leg, which stabilizes the leg to measure calf muscle strength.
METHODS: Muscle strength measurements of muscle tissue consist of 1) producing isometric strength at ankle angles of 80, 90, and 100 degrees of plantar flexion, 2) maximum torque at six isokinetic angular speeds of 0.52, 1.05, 2.09, 3 , 14, 4.19 and 5.24 happy xs (-1) and 3) fatigue test, consisting of 30 maximum cuts at 3.14 happy xs (-1). The greatest production of force occurred at 80 degrees of ankle plantar flexion (148.5 ± 40.2 Nm). The production of isokinetic power ranged from 114.1 ± 24.7 Nm at 0.52 rad xs (-1) to 16.8 ± 6.5 Nm at 5.24 rad xs (-1). The fatigue test, consisting of 30 maximum repetitions at 3.14 rad xs (-1), was allowed while reducing the power load by 61 +/- 15%. To assess reproduction and daily change, measurements of 1.05 and 2.09 rad xs (-1) were performed during five different tests in one day and one test per day for three days, respectively. The coefficient of variation within the subject was from 2.6 to 6.5% for reproducibility and from 1.9 to 7.4% for daily variation. Magnetic resonance imaging (MRI) of the mandible and muscle biopsy from the gastrocnemius muscle (lateral head) and the plantar muscles was obtained to study the relationship between the strength and the morphological characteristics of the leg muscles.
RESULTS: The cross-sectional area of the primary plantar flexors (gastronemia and soles) was 47.9 ± 1.3 cm2, and the volume of the muscles was 642 ± 16 cm3. The composition of the muscle fibers of the gastrocnemius muscle and the sole averaged 57 +/- 2 and 85 +/- 3% type I fibers, respectively. A poor correlation was found between fiber types and maximum isometric strength (r = 0.38, p> 0.05). However, the strength of the gastrocnemius muscle and the size of the muscles were positively correlated (r = 0.76; p). In this study, it was shown that the soleness corresponds mainly to type I fibers and the maximum gastrocnemius torque occurs at a knee angle of 160ยบ.
The effect of eccentric velocity on the elbow flexor activation: magnetic resonance imaging.
Kulig K, Powers CM, Shellock FG, Terk M.
Med Sci Sports Exerc 2001 Feb; 33 (2): 196-200
Department of Biokinesiology and Physical Therapy, University of Southern California
OBJECTIVE: to compare magnetic resonance imaging (MRI) in primary elbow flexors for two isotonic exercise protocols, varying in eccentric speed and the ratio of eccentric and concentric activity.
METHODS: Twelve people completed two exercise protocols. The right and left hands were randomly tied to one of two protocols that had the same workload (60% 1RM) and the same total training time (144 s), but differed in speed and ratio of eccentric and concentric activity (1: 1 and 5 : 1 for fast and slow protocols, respectively). MRI signal intensity changes were quantified for pre- and post-exercise using an inversion recovery sequence with a 1.5T MRI system (TR = 2500 ms, TE = 90 ms, TI = 140 ms). The percentage change in MRI signal intensity, perceived stress rate (RPE), and muscular muscle retention (DOMS) were recorded and analyzed.
It was found that the biceps brachii was preferable to recruit during the fast protocol compared to brachialis, whereas brachialis was found preferable to type during the slow protocol (P). This study shows that the rate may vary in the type of recruiting during curl hands.
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