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Martyn R. Shorten and Darcy S. Winslow

The purpose of this study was to determine the effects of increasing impact shock levels on the spectral characteristics of impact shock and impact shock wave attenuation in the body during treadmill running. Twelve male subjects ran at 2.0, 3.0, 4.0, and 5.0 m s−1 on a treadmill. Axial accelerations of the shank and head were measured using low-mass accelerometers. The typical shank acceleration power spectrum contained two major components which corresponded to the active (5–8 Hz) and impact (12–20 Hz) phases of the time-domain ground reaction force. Both the amplitude and frequency of leg shock transients increased with increasing running speed. Greatest attenuation of the shock transmitted to the head occurred in the 15–50 Hz range. Attenuation increased with increasing running speed. Thus transmission of the impact shock wave to the head was limited, despite large increases in impact shock at the lower extremity.

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Karla A. Kubitz and Daniel M. Landers

This study examined the effects of an 8-week aerobic training program on cardiovascular responses to mental stress. Dependent variables included electrocardiographic activity, blood pressure, electroencephalographic (EEG) activity, state anxiety, and state anger. Quantification of indicators of sympathetic, parasympathetic, and central nervous system activity (i.e., respiratory sinus arrhythmia, T-wave amplitude, and EEG activity, respectively) allowed examination of possible underlying mechanisms. Subjects (n = 24) were randomly assigned to experimental (training) and control (no training) conditions. Pre- and posttesting examined cardiorespiratory fitness and responses to mental stress (i.e., Stroop and mental arithmetic tasks). MANOVAs identified a significant effect on cardiorespiratory fitness, heart rate, respiratory sinus arrhythmia, and EEG alpha laterality. The results appear consistent with the hypothesis that enhanced parasympathetic nervous system activity and decreased central nervous system laterality serve as mechanisms underlying certain aerobic training effects.

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Richard Mullen, Lew Hardy, and Andrew Tattersall

The aim of this study was to examine the conscious processing hypothesis as an explanation of the anxiety/performance relationship. The study was designed to identify conscious processing performance effects while controlling for an alternative attentional threshold explanation identified in previous research. Participants completed 60 golf putts. They completed 3 blocks of 10 putts in single task, task-relevant shadowing, and task-irrelevant tone-counting conditions. Each set of 3 × 10 putts was completed in low and high anxiety conditions. Anxiety was elevated using an instructional set. Self-reported effort and spectral analysis of heart rate variability were used to examine the patterning of effort across the different putting conditions. Findings indicated that performance was impaired in the high anxiety shadowing and tone-counting conditions, supporting an attentional threshold interpretation. Spectral analysis of heart rate variability indicated that potential compensatory increases in spectral power in the high frequency band associated with dual-task putting in the low anxiety condition were absent in the high anxiety tone-counting and shadowing putting conditions, partially reflecting the performance findings. No effects were found for self-reported effort. Taken together, the performance and heart rate variability results support an attentional interpretation of the anxiety/motor performance relationship.

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Laurent Mourot, Nicolas Fabre, Aldo Savoldelli, and Federico Schena

To determine the most accurate method based on spectral analysis of heart-rate variability (SA-HRV) during an incremental and continuous maximal test involving the upper body, the authors tested 4 different methods to obtain the heart rate (HR) at the second ventilatory threshold (VT2). Sixteen ski mountaineers (mean ± SD; age 25 ± 3 y, height 177 ± 8 cm, mass 69 ± 10 kg) performed a roller-ski test on a treadmill. Respiratory variables and HR were continuously recorded, and the 4 SA-HRV methods were compared with the gas-exchange method through Bland and Altman analyses. The best method was the one based on a time-varying spectral analysis with high frequency ranging from 0.15 Hz to a cutoff point relative to the individual’s respiratory sinus arrhythmia. The HR values were significantly correlated (r 2 = .903), with a mean HR difference with the respiratory method of 0.1 ± 3.0 beats/min and low limits of agreements (around –6/+6 beats/min). The 3 other methods led to larger errors and lower agreements (up to 5 beats/min and around –23/+20 beats/min). It is possible to accurately determine VT2 with an HR monitor during an incremental test involving the upper body if the appropriate HRV method is used.

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Eryk P. Przysucha, M. Jane Taylor, and Douglas Weber

This study compared the nature of postural adaptations and control tendencies, between 7 (n = 9) and 11-year-old boys (n = 10) with Developmental Coordination Disorder (DCD) and age-matched, younger (n = 10) and older (n = 9) peers in a leaning task. Examination of anterior-posterior, medio-lateral, maximum and mean area of sway, and path length revealed one significant interaction as older, unaffected boys swayed more than all other groups (p < .01). As a group, boys with DCD displayed smaller anterior-posterior (p < .01) and area of sway (p < .01). Analysis of relative time spent in the corrective phase (p < .002) revealed that boys with DCD spent 54% under feedback control while boys without DCD spent 78%. This was attributed to reduced proprioceptive sensitivity, as confirmed by significant differences between the groups (p < .009) in spectral analysis of peak frequency of sway.

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Original Investigations Objective Biomechanical Determination of Tennis Racket Properties Herbert Hatze * 11 1992 8 4 275 287 10.1123/ijsb.8.4.275 Research Spectral Analysis of Impact Shock during Running Martyn R. Shorten * Darcy S. Winslow * 11 1992 8 4 288 304 10.1123/ijsb.8.4.288 Archery

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Anat V. Lubetzky, Bryan D. Hujsak, Gene Fu, and Ken Perlin

highly significant ( p  < .009) on both test and retest on all comparisons but the following: test: pitch rotation ( p  = .03), X translation ( p  = .005), yaw rotation ( p  = .14), and roll rotation ( p  = .03); and retest: yaw rotation ( p  = .004). Figure 5 —Histograms derived from spectral analysis

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Alexei Wong and Arturo Figueroa

spectral analysis of the R-R intervals was performed by the autoregressive model using the WinCPRS software (Absolute Aliens Oy, Turku, Finland). As a time domain index of HRV, we calculated the root mean square of successive differences (RMSSD), which reflects parasympathetic modulation ( Kleiger, Stein

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Alexei Wong, Arturo Figueroa, Marcos A. Sanchez-Gonzalez, Won-Mok Son, Oksana Chernykh, and Song-Young Park

of Rheumatology, 28 ( 3 ), 581 – 589 . PubMed Cohen , H. , Neumann , L. , Shore , M. , Amir , M. , Cassuto , Y. , & Buskila , D. ( 2000 ). Autonomic dysfunction in patients with fibromyalgia: Application of power spectral analysis of heart rate variability . Seminars in Arthritis

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Piia Kaikkonen, Esa Hynynen, Arto Hautala, and Juha P. Ahtiainen

R . Hemodynamic regulation: investigation by spectral analysis . Am J Physiol . 1985 ; 249 : H867 – H875 . PubMed ID: 4051021 4051021 2. Martinmäki K , Rusko H , Kooistra L , Kettunen J , Saalasti S . Intraindividual validation of heart rate variability indices to measure vagal