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Accuracy of 1 Hz versus 5 Hz GPS devices to measure movement patterns in team sport activities
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2010 Asics Conference of Science and Medicine in Sport / Journal of Science and Medicine in Sport 13S (2010) e1–e107
measuring girths on females, especially waist girths on lean females. doi:10.1016/j.jsams.2010.10.527 67
68 Accuracy of 1 Hz versus 5 Hz GPS devices to measure movement patterns in team sport activities P. Gastin ∗ , K. Williams Deakin University, Australia
The effect of the use of a mouthpiece and nose clip on heart rate variability R. Beavers ∗ , S. Treacy, A. Davie Southern Cross University, Australia Aim: The aim of this study was to determine the potential impact of breathing through a mouthpiece and nose clip assembly, such as the Hans Rudolph system used in exercise testing, on autonomic modulation of heart rate, as assessed by measures of heart rate variability (HRV) during seated rest. Methods: Ten participants (2 M and 8 F, mean age 53.5 ± 2.68 years, BMI 25.80 ± 3.29 kg/m2 ) sat quietly for 5 min to establish resting conditions, then breathed utilizing the mouthpiece and nose clip (MP1) for 5 min then without for five minutes (NMP1), and repeated this procedure (MP2 and NMP2). ECG was recorded continuously for the duration of the test and HRV measures of SDNN, total power, very low frequency (VLF); high frequency (HF) and low frequency (LF), LF and HF normalized values and the LF/HF ratio were later calculated using Chart 5 pro software (Adinstruments). Results: ANOVA results show heart rate averages remained within one beat per minute across conditions, while measures of SDNN, VLF and Total Power were significantly greater in the NMP2 condition than MP1 and MP2; these measures for the NMP1 condition were also greater in magnitude but did not reach significance. LF normalized values were reduced in the MP conditions (MP1 0.566 ± 0.147nu, NMP1 0.708 ± 0.155nu, MP2 0.606 ± 0.129nu and NMP2 0.765 ± 0.120nu), while HF normalized values were significantly greater in the comparison of MP1 to NMP1 (p = 0.017) and approached significance in MP2 and NMP2 (p = 0.054). The LF/HF ratio was significantly greater in both NMP1 and NMP2 than both MP1 and MP2. Conclusion: the MP condition resulted in changes in measures of HRV. These changes may be the result of alterations in breathing induced by use of the MP and/or alterations in autonomic modulation of heart rate between the two conditions. This may be of relevance in studies using HRV in exercise testing. doi:10.1016/j.jsams.2010.10.528
Introduction: The use of global positioning system (GPS) devices to measure movement demands in team sports is becoming increasingly popular. Manufacturer enhancements to the application of this technology are also evident with sample frequency recently upgraded from 1 Hz to 5 Hz. Given the running and frequent change of direction demands associated with team sports activities, it has been suggested that increased GPS sampling frequency would provide greater accuracy in measuring these movement patterns. Methods: To assess this hypothesis, two team sport athletes were recruited to complete eight bouts of six laps of a 128.5 m intermittent running circuit designed to simulate typical team sport running patterns (N = 96). On a subsequent day straight line and zig-zag 50 m repeats at speeds relating to walk, stride and sprint were completed (N = 96; 16 trials at each course-gait combination). Distance and speed were assessed concurrently using 1 Hz and 5 Hz GPS devices (SPI Elite & SPI Pro, GPSports, Australia). Results: Mean lap distances (±SD; N = 96) were within 1 m of the measured circuit for the 1 Hz (127.7 ± 1.9) and 5 Hz (127.5 ± 4.0) devices, with the coefficient of variation (CV) being lower for 1 Hz (1.5%) compared to 5 Hz (3.1%). Peak speeds, measured over the last 5 m of a 20 m sprint within the circuit, were within −1.9% for 1 Hz and +0.2% for 5 Hz of that of a timing gate criterion measure (25.7 ± 1.2 km h−1 ). Total distance recorded within a very high intensity speed zone (>20 km h−1 ) over a bout of 771 m was significantly greater for the 5 Hz (150.3 ± 1.2 km h−1 ) compared to the 1 Hz device (135.0 ± 16.3 km h−1 ). During straight line efforts the 1 Hz device recorded distances closer to the actual distance (50.2 ± 2.4 m compared to 47.9 ± 1.5 m) with no differences being observed between the different gaits. During the zigzag efforts, both units significantly underestimated the actual distance (1 Hz: 45.9 ± 2.6 m; 5 Hz: 46.2 ± 1.6 m), this being more evident at the faster speeds. Conclusion: For intermittent running and change of direction movement tasks, increasing sampling frequency of GPS technology from 1 Hz to 5 Hz does not appear to enhance the accuracy of measurement for short running efforts, although over a longer distance and time, greater detection of very high intensity running is evident. doi:10.1016/j.jsams.2010.10.529
2010 Asics Conference of Science and Medicine in Sport / Journal of Science and Medicine in Sport 13S (2010) e1–e107
measuring girths on females, especially waist girths on lean females. doi:10.1016/j.jsams.2010.10.527 67
68 Accuracy of 1 Hz versus 5 Hz GPS devices to measure movement patterns in team sport activities P. Gastin ∗ , K. Williams Deakin University, Australia
The effect of the use of a mouthpiece and nose clip on heart rate variability R. Beavers ∗ , S. Treacy, A. Davie Southern Cross University, Australia Aim: The aim of this study was to determine the potential impact of breathing through a mouthpiece and nose clip assembly, such as the Hans Rudolph system used in exercise testing, on autonomic modulation of heart rate, as assessed by measures of heart rate variability (HRV) during seated rest. Methods: Ten participants (2 M and 8 F, mean age 53.5 ± 2.68 years, BMI 25.80 ± 3.29 kg/m2 ) sat quietly for 5 min to establish resting conditions, then breathed utilizing the mouthpiece and nose clip (MP1) for 5 min then without for five minutes (NMP1), and repeated this procedure (MP2 and NMP2). ECG was recorded continuously for the duration of the test and HRV measures of SDNN, total power, very low frequency (VLF); high frequency (HF) and low frequency (LF), LF and HF normalized values and the LF/HF ratio were later calculated using Chart 5 pro software (Adinstruments). Results: ANOVA results show heart rate averages remained within one beat per minute across conditions, while measures of SDNN, VLF and Total Power were significantly greater in the NMP2 condition than MP1 and MP2; these measures for the NMP1 condition were also greater in magnitude but did not reach significance. LF normalized values were reduced in the MP conditions (MP1 0.566 ± 0.147nu, NMP1 0.708 ± 0.155nu, MP2 0.606 ± 0.129nu and NMP2 0.765 ± 0.120nu), while HF normalized values were significantly greater in the comparison of MP1 to NMP1 (p = 0.017) and approached significance in MP2 and NMP2 (p = 0.054). The LF/HF ratio was significantly greater in both NMP1 and NMP2 than both MP1 and MP2. Conclusion: the MP condition resulted in changes in measures of HRV. These changes may be the result of alterations in breathing induced by use of the MP and/or alterations in autonomic modulation of heart rate between the two conditions. This may be of relevance in studies using HRV in exercise testing. doi:10.1016/j.jsams.2010.10.528
Introduction: The use of global positioning system (GPS) devices to measure movement demands in team sports is becoming increasingly popular. Manufacturer enhancements to the application of this technology are also evident with sample frequency recently upgraded from 1 Hz to 5 Hz. Given the running and frequent change of direction demands associated with team sports activities, it has been suggested that increased GPS sampling frequency would provide greater accuracy in measuring these movement patterns. Methods: To assess this hypothesis, two team sport athletes were recruited to complete eight bouts of six laps of a 128.5 m intermittent running circuit designed to simulate typical team sport running patterns (N = 96). On a subsequent day straight line and zig-zag 50 m repeats at speeds relating to walk, stride and sprint were completed (N = 96; 16 trials at each course-gait combination). Distance and speed were assessed concurrently using 1 Hz and 5 Hz GPS devices (SPI Elite & SPI Pro, GPSports, Australia). Results: Mean lap distances (±SD; N = 96) were within 1 m of the measured circuit for the 1 Hz (127.7 ± 1.9) and 5 Hz (127.5 ± 4.0) devices, with the coefficient of variation (CV) being lower for 1 Hz (1.5%) compared to 5 Hz (3.1%). Peak speeds, measured over the last 5 m of a 20 m sprint within the circuit, were within −1.9% for 1 Hz and +0.2% for 5 Hz of that of a timing gate criterion measure (25.7 ± 1.2 km h−1 ). Total distance recorded within a very high intensity speed zone (>20 km h−1 ) over a bout of 771 m was significantly greater for the 5 Hz (150.3 ± 1.2 km h−1 ) compared to the 1 Hz device (135.0 ± 16.3 km h−1 ). During straight line efforts the 1 Hz device recorded distances closer to the actual distance (50.2 ± 2.4 m compared to 47.9 ± 1.5 m) with no differences being observed between the different gaits. During the zigzag efforts, both units significantly underestimated the actual distance (1 Hz: 45.9 ± 2.6 m; 5 Hz: 46.2 ± 1.6 m), this being more evident at the faster speeds. Conclusion: For intermittent running and change of direction movement tasks, increasing sampling frequency of GPS technology from 1 Hz to 5 Hz does not appear to enhance the accuracy of measurement for short running efforts, although over a longer distance and time, greater detection of very high intensity running is evident. doi:10.1016/j.jsams.2010.10.529