Exercises for the Torso Performed in a Standing Posture: Spine and Hip Motion and Motor Patterns and Spine Load
Department of Kinesiology, Faculty of Applied Health Sciences, Spine Biomechanics Laboratories, University of Waterloo, Waterloo, Canada. The Journal of Strength and Conditioning Research
(Impact Factor: 2.08).
04/2009; 23(2):455-64. DOI: 10.1519/JSC.0b013e3181a0227e
The purpose of this study was to document the muscle activity, spine motion, spine load, and stiffness during several movement-based or "functional" exercises and to assess the effect of technique change. Eight subjects, all healthy men from a university population, were instrumented to obtain surface electromyography of selected trunk and hip muscles, together with video analysis and electromagnetic lumbar spine position sensor to track spine posture. Exercises included a walkout in the sagittal plane that compared an upright form against a wall with those performed on the floor, overhead cable pushes, lateral cable walkouts, the good morning exercise, and the bowler's squat. Generally, muscle activation levels were quite modest even though the tasks were quite strenuous in many cases. Even though similar joint moments were required in different exercises, the pattern of activity between muscles was different. Abdominal bracing increased spine stiffness at the expense of more spine load. Thus, muscle activity seems to be constrained in "functional" exercises. There are several possible reasons for this. Single muscles cannot be activated to 100% of the maximum voluntary contraction in functional exercises because this would upset the balance of moments about the 3 orthopedic axes of the spine, or it would upset the balance of stiffening muscles around the spine required to ensure stability of the spinal column. The one exception was the floor walkout, which resulted in full activation of the rectus abdominis; however, this was a sagittal plane task without the joint moment constraints of multiplanar exercise. Therefore, maximal muscle activity is observed during single-plane tasks, but muscle activation levels were constrained during functional tasks. Thus, strength training muscles may not help in "functional multiplanar" tasks. These data can be used to assist decisions regarding the selection of exercises, specifically choices regarding the starting challenge, progression, exercise form, and possibly corrective technique for those who have spine concerns, or those simply looking for performance enhancement.
Available from: Andrew D Vigotsky
- "and right thoracic erector spinae 5 cm lateral to spinous process T9 (TES) (Konrad, 2005; McGill et al., 2009). Lumbar flexion was calculated by placing 25.4 mm spherical markers on T11, L1, and S2, and a 14.0 mm marker on the ASIS (Kuo, Tully & Galea, 2009a; Kuo, Tully & Galea, 2009b; Kuo, Tully & Galea, 2009c). "
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ABSTRACT: Many strength and conditioning coaches utilize the good morning (GM) to strengthen the hamstrings and spinal erectors. However, little research exists on its electromyography (EMG) activity and kinematics, and how these variables change as a function of load. The purpose of this investigation was to examine how estimated hamstring length, integrated EMG (IEMG) activity of the hamstrings and spinal erectors, and kinematics of the lumbar spine, hip, knee, and ankle are affected by changes in load. Fifteen trained male participants (age = 24.6 ± 5.3 years; body mass = 84.7 ± 11.3 kg; height = 180.9 ± 6.8 cm) were recruited for this study. Participants performed five sets of the GM, utilizing 50, 60, 70, 80, and 90% of one-repetition maximum (1RM) in a randomized fashion. IEMG activity of hamstrings and spinal erectors tended to increase with load. Knee flexion increased with load on all trials. Estimated hamstring length decreased with load. However, lumbar flexion, hip flex-ion, and plantar flexion experienced no remarkable changes between trials. These data provide insight as to how changing the load of the GM affects EMG activity, kinematic variables, and estimated hamstring length. Implications for hamstring injury prevention are discussed. More research is needed for further insight as to how load affects EMG activity and kinematics of other exercises.
PeerJ 01/2015; 2:e708. DOI:10.7717/peerj.708 · 2.11 Impact Factor
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ABSTRACT: As functional resistance training becomes a more popular method to improve muscular fitness, questions remain regarding the effectiveness of functional training compared to traditional resistance training. Therefore, the purpose of this study was to determine whether functional training has similar effects as traditional resistance training on muscular strength and endurance, flexibility, agility, balance, and anthropometric measures in young adults. In this study, 38 healthy volunteers, aged 18-32 years, were randomly placed into a control group [traditional (n = 19)] and an experimental group [functional (n = 19)]. The participants were tested prior to and after completing the 7-week training study. The testing battery included: weight, girth measurements, flexibility, agility, lower back flexion and extension endurance, push-up test, sit-up test, one-leg balance, one-repetition maximum (1-RM) bench press and squat. Results indicated significant (p < 0.05) increases in push-ups, back extension endurance, 1-RM bench press, 1-RM squat, and one-leg balance within each group following training. Traditional training also elicited significant (p < 0.05) increases in bicep girth, forearm girth, calf girth, and sit-ups, while the functional training group experienced significant (p < 0.05) increases in shoulder girth and flexibility. Forearm girth and flexion test time changes following training were the only parameter where there were significant (p < 0.05) differences between training groups. Collectively, these results suggest that both programs are equally beneficial for increasing endurance, balance, and traditional measures of strength. However, changes in various girth measures, torso flexor endurance and flexibility appear to be program-specific.
Journal of exercise science and fitness (JESF) 05/2010; 42(2). DOI:10.1249/01.MSS.0000384421.59086.32 · 0.33 Impact Factor
Available from: Stuart M Mcgill
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ABSTRACT: THIS REVIEW ARTICLE RECOGNIZES THE UNIQUE FUNCTION OF THE CORE MUSCULATURE. IN MANY REAL LIFE ACTIVITIES, THESE MUSCLES ACT TO STIFFEN THE TORSO AND FUNCTION PRIMARILY TO PREVENT MOTION. THIS IS A FUNDAMENTALLY DIFFERENT FUNCTION FROM THOSE MUSCLES OF THE LIMBS, WHICH CREATE MOTION. BY STIFFENING THE TORSO, POWER GENERATED AT THE HIPS IS TRANSMITTED MORE EFFECTIVELY BY THE CORE. RECOGNIZING THIS UNIQUENESS, IMPLICATIONS FOR EXERCISE PROGRAM DESIGN ARE DISCUSSED USING PROGRESSIONS BEGINNING WITH CORRECTIVE AND THERAPEUTIC EXERCISES THROUGH STABILITY/MOBILITY, ENDURANCE, STRENGTH AND POWER STAGES, TO ASSIST THE PERSONAL TRAINER WITH A BROAD SPECTRUM OF CLIENTS.
Strength and conditioning journal 05/2010; 32(3):33-46. DOI:10.1519/SSC.0b013e3181df4521 · 0.60 Impact Factor
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