dominant TFL was identified in subjects who were unable to adduct the leg parallel to the table in a neutral position. 1 Measurement Surface electromyography (EMG; Noraxon TeleMyo DTS; Noraxon Inc, Scottsdale, AZ) was used to collect muscle activity and onset time data on the GMED, TFL, and AL on the
Hae-rim Han, Chung-hwi Yi, Sung-hyun You, Heon-seock Cynn, One-bin Lim and Jae-ik Son
John H. Hollman, Tyler A. Berling, Ellen O. Crum, Kelsie M. Miller, Brent T. Simmons and James W. Youdas
.1249/01.MSS.0000078924.61453.FB 12900694 15. Criswell E . Cram’s Introduction to Surface Electromyography . 2nd ed. Sudbury, MA : Jones and Bartlett Publishers ; 2011 . 16. Hislop HJ , Montgomery J . Daniels and Worthingham’s Muscle Testing: Techniques of Manual Examination . 8th ed. St
Benjamin S. Killen, Krista L. Zelizney and Xin Ye
European Recommendations for Surface ElectroMyoGraphy: Result of the SENIAM Project . Enschede, The Netherlands : Roessingh Research and Development ; 1999 . 30. Cohen J . A power primer . Psychol Bull . 1992 ; 112 ( 1 ): 155 – 159 . PubMed ID: 19565683 doi:10.1037/0033-2909.112.1.155 19565683 10
Lucinda E. Bouillon, Michael Hofener, Andrew O’Donnel, Amanda Milligan and Craig Obrock
between the iliac crest and base of the patella 15 Tibialis anterior Parallel and just lateral to the medial shaft of the tibia, approximately one-fourth to one-third of distance between the knee and ankle 15 For normalization of surface electromyography (SEMG) data, 3 maximal voluntary isometric
Andrew L. McDonough and Joseph P. Weir
The purpose of this case study was to investigate reflex inhibition of the quadriceps femoris in a subject with postsurgical edema of the left knee. The subject was a 45-year-old male with a traumatic knee injury with resultant edema who underwent elective arthroscopic surgery. Reflex inhibition was assessed by H-reflex elicitation in the femoral nerve and surface electromyography of the quadriceps. To assess the degree of edema, direct circumferential measurements were taken. On the first presurgical visit, the left knee demonstrated mild edema with a decrease in H-reflex amplitudes. Two days after surgery, a further reduction in amplitudes and more swelling were demonstrated followed by an increase in amplitudes and a reduction in edema on the 28th postoperative day. These findings document a relationship between reflex inhibition and joint swelling that was previously described in experimental models where joint edema was simulated.
Gretchen D. Oliver, Audrey Stone and Jessica Washington
Recently, sports medicine professionals have shown interest in using dynamic movement assessments to help identify biomechanical risk factors for musculoskeletal injury. Thus the purpose of this study was to propose two movements (single leg step down and single leg lateral hop) that could predict injury and determine if these proposed movements elicited muscle activation of the hamstrings and gluteals. Surface electromyography was employed and muscle activations of the hamstrings and gluteus medius muscles were classified as strong during both the single leg step down (SLSD) and single leg lateral hop (SLLH). Both the hamstrings and gluteus medius muscles are associated with musculoskeletal injury. The SLSD and SLLH cause significantly high muscle activation of both these muscle groups and should be considered for use in dynamic movement assessments.
Gretchen Oliver, Lisa Henning and Hillary Plummer
The purpose of this study was to examine activations of selected scapular stabilizing musculature while performing an overhead throw with a hold (not releasing the ball) in two different throwing positions—standing with a crow hop and kneeling on the ipsilateral knee. Surface electromyography was used to examine activations of throwing side lower trapezius (LT), middle trapezius (MT), serratus anterior (SA), and upper trapezius (UT). Muscle activations were recorded while performing the overhead throw with holds while in two throwing positions. MANOVA results revealed no significant differences between the two throwing conditions and muscle activations of LT, MT, SA, and UT: F(8,124) = .804, p = .600; Wilks’s Λ = .904, partial η2 = .049. Although no significant differences were observed in the scapular stabilizers between the two conditions, moderate (21–50% MVIC) to high (> 50% MVIC) activations of each muscle were present, indicating that nonrelease throws may be beneficial for scapular stabilization in throwers.
Douglas P. Jowdy and Dorothy V. Harris
The purpose of the present investigation was to determine if the magnitude of muscular activity concomitant with mental imagery is a function of motor skill level. Male undergraduates (N=38) between 18 and 24 years of age were assigned to either a high skilled (n=23) or low skilled (n = 15) group of jugglers. All subjects completed the Movement Imagery Questionnaire (MIQ) (Hall & Pongrac, 1983) and imagined themselves juggling for eight 15-second trials while the amplitude of muscular activity was measured by surface electromyography. There was a significant increase in muscular activity during mental imagery across all subjects (p<.001), but the difference between the high and low skilled groups was not significant. This lack of difference may suggest that the differential effects of imagery based upon skill level are not due to the neuromuscular activation during imagery.
Kevin R. Ford, Gregory D. Myer, Laura C. Schmitt, Timothy L. Uhl and Timothy E. Hewett
The purpose of this study was to identify alterations in preparatory muscle activation patterns across different drop heights in female athletes. Sixteen female high school volleyball players performed the drop vertical jump from three different drop heights. Surface electromyography of the quadriceps and hamstrings were collected during the movement trials. As the drop height increased, muscle activation of the quadriceps during preparatory phase also increased (p < .05). However, the hamstrings activation showed no similar increases relative to drop height. Female athletes appear to preferentially rely on increased quadriceps activation, without an increase in hamstrings activation, with increased plyometric intensity. The resultant decreased activation ratio of the hamstrings relative to quadriceps before landing may represent altered dynamic knee stability and may contribute to the increased risk of ACL injury in female athletes.
Emmanuel Jacobs, Nathalie Roussel, Ine Van Caekenberghe, Edith Cassiers, Luc Van den Dries, Jonas Rutgeerts, Jan Gielen and Ann Hallemans
This cross-sectional study aimed at developing a biomechanical method to objectify voluntary and unpredictable movements, using an automated three-dimensional motion capture system and surface electromyography. Fourteen experienced theater performers were tested while executing the old man exercise, wherein they have to walk like an old man, building up a sustained high intensive muscular activity and tremor. Less experienced performed showed a different kinematics of movement, a slower speed of progression and more variable EMG signals at higher intensity. Female performers also differed from males in movement kinematics and muscular activity. The number of the trial only influenced the speed of progression. The performers showed results which could be well placed within the stages of learning and the degrees of freedom problem.