magnitude, the frequency, the direction, and the duration of the oscillations combine to cause loss of balance. In trains, buses, aircraft, buildings, and so on, the motions causing instability are often transient, so it is desirable to understand whether instability can be predicted from a peak measure of
Hatice Mujde Ayık and Michael J. Griffin
Matt Hausmann, Jacob Ober and Adam S. Lepley
motion and strength deficits. 1 Due to these impairments, proper treatment is necessary to avoid additional loss of play and prevent future injuries. Recently, there has been an increased use of deep oscillation therapy by clinicians to manage pain and swelling following a variety of injuries, including
Zachary K. Winkelmann, Ethan J. Roberts and Kenneth E. Games
and in turn increase muscle extensibility. 3 However, it is now postulated that the increases in flexibility are due to the stimulation of nerves that modify sensation, which results in increased flexibility. 4 , 5 One such modality that claims to increase flexibility is deep oscillation therapy (DOT
Temporal and spatial movement characteristics are often seen as controlled separately, although they are not independent. Even in the case of simple oscillations mean frequency and mean amplitude covary when one or the other is changed intentionally. The present experiment revealed that in rapid finger oscillations there is also a cycle-to-cycle covariation so that smaller amplitudes are associated with locally increased frequency and (the associated) earlier electromyographic (EMG) bursts. Both globally and locally the observed covariations are consistent with modeling rhythmic movements as output of a driven damped oscillator. The existence of local spatio-temporal covariations suggests limitations for models of timing and reasons for the observation that spatio-temporal movement characteristics cannot be chosen arbitrarily even in uniarticular movements.
Stéphane Morin, Saïd Ahmaïdi and Pierre-Marie Leprêtre
Positive and negative effects of training induce apparent oscillations of performance, suggesting that the delayed cumulative effects of training on daily performance capacity (DPC) are best fitted by sine waves damped over time.
To compare the criterion validity of the impulse-response (IR) model of Banister et al and the damped harmonic oscillation (DHO) model for quantifying the training load (TL)–DPC relationship.
Six female professional volleyball players (20.8 ± 2.4 y) were monitored using the session rating of perceived exertion (sRPE) for 9 mo to quantify TL. Countermovement-jump (CMJ) and 4-step-approach-CMJ (4sCMJ) performances were recorded once a month. Parameters of models were determined by minimizing residual-sum squares between predicted and real performances with a nonlinear regression.
DPC was best fitted by the DHO model rather than the IR model (CMJ, R 2 = .80 ±.08 and.69 ±.20, respectively; 4sCMJ, R 2 = .86 ± .09 and .67 ± .29, respectively). The damping parameter θ and the period T were positively correlated with age (ρ = 0.81, P < .05, and ρ = 0.86, P < .02, respectively).
The DHO model is a useful tool for modeling DPC as the sum of the delayed DPCs from the consecutive training and recovery days. DPC could be considered the expression of the individual process of accumulation and dissipation of fatigue induced by training. DHO-model parameters were correlated with age, which prompts one to postulate that expertise has a major influence on DPC. The DHO model will help coaches develop a greater understanding of training effects and make monitoring of the training process more effective.
Ricky Watari, Blayne Hettinga, Sean Osis and Reed Ferber
The purpose of this study was to validate measures of vertical oscillation (VO) and ground contact time (GCT) derived from a commercially-available, torso-mounted accelerometer compared with single marker kinematics and kinetic ground reaction force (GRF) data. Twenty-two semi-elite runners ran on an instrumented treadmill while GRF data (1000 Hz) and three-dimensional kinematics (200 Hz) were collected for 60 s across 5 different running speeds ranging from 2.7 to 3.9 m/s. Measurement agreement was assessed by Bland-Altman plots with 95% limits of agreement and by concordance correlation coefficient (CCC). The accelerometer had excellent CCC agreement (> 0.97) with marker kinematics, but only moderate agreement, and overestimated measures between 16.27 mm to 17.56 mm compared with GRF VO measures. The GCT measures from the accelerometer had very good CCC agreement with GRF data, with less than 6 ms of mean bias at higher speeds. These results indicate a torsomounted accelerometer provides valid and accurate measures of torso-segment VO, but both a marker placed on the torso and the accelerometer yield systematic overestimations of center of mass VO. Measures of GCT from the accelerometer are valid when compared with GRF data, particularly at faster running speeds.
Yi-Chung Pai and James G. Hay
The purpose of this study was to determine the validity of the quasi-static assumption—that fluid forces exerted under unsteady flow conditions are equal to those exerted under similar steady flow conditions—in the case of a cylindrical model oscillating in a vertical plane about a transverse axis normal to the flow. The findings indicated that the quasi-static approach is applicable only to cyclic motions with low frequencies and small accelerations. For swimming motions that involve high frequencies and high accelerations, like those that occur in competitive swimming, the vortex shedding effect and the added mass effect must be taken into account if accurate values are to be obtained for hydrodynamic forces.
Jennifer L. Lister, Gianluca Del Rossi, Fangchao Ma, Mark Stoutenberg, Jessica B. Adams, Sara Tobkin and Joseph F. Signorile
There are numerous ways to overload the scapular stabilizers.
To assess scapular stabilizer activity using the Bodyblade® and other traditional training devices.
Repeated measures analysis of surface EMG data collected from the upper trapezius (UT), lower trapezius (LT), and serratus anterior (SA) during shoulder flexion and abduction using Bodyblade®, cuff weight, and Thera-Band® resistance.
Thirty collegiate athletes (20.0 ± 1.7 years).
Participants performed 10 repetitions of shoulder flexion and abduction.
Main Outcome Measures:
For each movement, normalized root mean square values (NrmsEMG) were computed for each muscle during each repetition under each training condition. Data were analyzed using 3 (condition) × 10 (repetition) repeated measures ANOVAs.
During shoulder flexion and abduction, the NrmsEMG of the UT, LT, and SA were significantly greater when using the Bodyblade® than the Thera-Band® or cuff weight.
The Bodyblade® produces greater scapular activity than traditional resistance techniques.
Dennis-Peter Born, Billy Sperlich and Hans-Christer Holmberg
To assess original research addressing the effect of the application of compression clothing on sport performance and recovery after exercise, a computer-based literature research was performed in July 2011 using the electronic databases PubMed, MEDLINE, SPORTDiscus, and Web of Science. Studies examining the effect of compression clothing on endurance, strength and power, motor control, and physiological, psychological, and biomechanical parameters during or after exercise were included, and means and measures of variability of the outcome measures were recorded to estimate the effect size (Hedges g) and associated 95% confidence intervals for comparisons of experimental (compression) and control trials (noncompression). The characteristics of the compression clothing, participants, and study design were also extracted. The original research from peer-reviewed journals was examined using the Physiotherapy Evidence Database (PEDro) Scale. Results indicated small effect sizes for the application of compression clothing during exercise for shortduration sprints (10–60 m), vertical-jump height, extending time to exhaustion (such as running at VO2max or during incremental tests), and time-trial performance (3–60 min). When compression clothing was applied for recovery purposes after exercise, small to moderate effect sizes were observed in recovery of maximal strength and power, especially vertical-jump exercise; reductions in muscle swelling and perceived muscle pain; blood lactate removal; and increases in body temperature. These results suggest that the application of compression clothing may assist athletic performance and recovery in given situations with consideration of the effects magnitude and practical relevance.
Karinna Sonálya Aires da Costa, Daniel Tezoni Borges, Liane de Brito Macedo, Caio Alano de Almeida Lins and Jamilson Simões Brasileiro
postural oscillation in subjects who underwent ACL reconstruction. In this study, we chose to use a combination of evaluation methods that are considered the gold standard in literature, such as isokinetic dynamometer, electromyography, and baropodometry. We hypothesized that the exercise protocol in WBV