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Increases in Variation of Barbell Kinematics Are Observed with Increasing Intensity in a Graded Back Squat TestCarroll, Kevin M., Sato, Kimitake, Bazyler, Caleb D., Triplett, N. Travis, Stone, Michael H. 14 July 2017 (has links)
The purpose of the current study was two-fold: (1) To examine the variation in velocity and power with increasing intensity in the back squat among subjects; and (2) To explore individual subject characteristics as possible explanations for variations of velocity in the back squat. Fourteen recreationally trained male subjects with experience in the back squat agreed to participate in the study (age = 25.0 ± 2.6 years, height = 178.9 ± 8.1 cm, body mass = 88.2 ± 15.8 kg). One-repetition maximums (1RM) were performed for each subject on force platforms with four linear position transducers attached to the barbell. The 1RM assessment was immediately preceded by warm-up sets at 65%, 75%, 85%, and 95% of estimated 1RM for 5, 3, 2, and 1 repetitions, respectively. Mean concentric velocity (MCV) and mean power were recorded for each intensity condition and were analyzed using Pearson correlation to determine the relationship between each variable and relative intensity (%1RM). Statistically significant negative relationships existed between %1RM and MCV (r = −0.892) and mean power (r = −0.604). Between-subject coefficient of variation tended to increase as %1RM increased for both MCV and mean power. These results suggest that MCV is superior to mean power as an indicator of relative intensity in the back squat. Additionally, the between-subject variation observed at higher intensities for MCV and mean power support the use of velocity ranges by strength and conditioning coaches.
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Concurrent Validity, Inra-unit, and Inter-unit Reliability of the Vmaxpro for Measuring VelocityStåhl, Elias January 2021 (has links)
The purpose of the present study was to evaluate the concurrent validity, intra-unit, and interunit reliability of the IMU Vmaxpro for measuring velocity for VBT purposes. Two protocols were constructed to cover velocities seen in the practical environment. Utilizing the 1080 Quantum the first protocol collected data without the use of subjects. For the second protocol, six well-trained men (age: 25.7 ± 4.2 years, standing height: 185.8 ± 10.6 cm, bodyweight: 87.3 ± 9.1 kg) performed loaded countermovement jumps. Two Vmaxpros and a 1080 Quantum simultaneously recorded repetitions for mean and peak velocity. Linear regression, RMSE, Bland-Altman, TE, and SDC were used to evaluate the concurrent validity, intra-unit, and inter-unit reliability. A strong relationship was found for MV and PV (R2 = 0.991– 0.997, RMSE = 0.044 – 0.05), p < 0.05) as well as a strong agreement on both protocols (bias: -0.039 – 0.072 on Protocol 1 and bias: 0.155 – - 0.005 on Protocol 2). The Vmaxpro showed strong reliability scores for within (MV: TE = 0.013 – 0.021; PV: TE = 0.017 – 0.023), and between sessions (MV: TE = 0.014 – 0.020; PV: TE = 0.019 – 0.027). Inter-unit reliability was acceptable to strong for both MV (TE = 0.012 – 0.034) and PV (TE = 0.021 – 0.057). The Vmaxpro can provide valid and reliable measurements for VBT purposes when using a single sensor. However, the inter-unit reliability showed a magnitude of variance which suggests practitioners not to use multiple devices interchangeably, and if so, it should be done with caution.
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Plate Tectonic Evolution and Mineral Resource Potential of the Lancang River Zone, Southwestern Yunnan, People's Republic of China / Plattentektonische und metallogenetische Entwicklung der Lancang River-Zone, Südwest-Yunnan, Volksrepublik ChinaHeppe, Klaus 09 June 2004 (has links)
No description available.
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