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12. Response-Methodological issues associated with the use of force plates when assessing push-ups power

Author

Wang R, Hoffman J, Sadres E, Bartolomei S, Muddle TWD, Fukuda S, Stout J R., Wang R, Hoffman J, Sadres E, Bartolomei S, Muddle TWD, Fukuda S, and Stout J R.

Subjects
power assessment, bench press, maximal strength
Abstract

We read with interest the article by Wang et al. (5). The authors calculated the peak power and mean power of ballistic push-ups as the highest and average power output using similar methods as for lower-body jump squats assessment (i.e., force-plate technique). We believe that the evaluation of power in Wang et al.'s (5) study is based on a misinterpretation of the articles cited in their study. Specifically, Hogarth et al.'s (4) study performed measures which indicate the performance of the exercises but did not actually evaluate power. However, Cormie et al.'s (1) study compared different methods of estimating peak power output. There are sufficient and necessary conditions that have to be respected in order to be able to correctly estimate the power on lower-limb dynamic exercises. We believe that Wang et al. (5) have in appropriately applied this method to the upper-limbs, for the following reasons: Cormie et al. (1) demonstrated that the force-plate technique underestimates the velocity and power output. In addition, this approach assumes linear kinetics, whereas the push-up movement involves rotation of the body about the toes. Moreover, in the push-ups, contrary to the vertical jump where the hands are “free,” both the hands and feet are in contact with the ground so all ground reaction forces should be measured. Nevertheless, only one part of the external forces were measured (hand-related forces) in the experimental protocol in the study of Wang et al. (5). The power provided in lower-limb vertical jump articles (1,3) is linear as the body moves upward in a linear motion. However, the trajectory of the center of mass of the body in the longitudinal plane when performing jump/ballistic push-ups is a circular arc around the toes (fixed point). A kinematic analysis is therefore needed to verify the path of the push-up and quantify the errors in power estimated when it is assumed that the push-up jump movement is perfectly vertical. We believe that this “transposed” technique used with the lower-limb to the upper-limbs is inappropriate. This takes on assumptions and can cause large measurement errors. We therefore suggest either (a) using some indices that are related to components of power without actual measurement of power (2), such as rate of force development, impulse, and flight-time, or (b) using 2 synchronized force-plates, which allow supporting the whole body in push-up position. We hope our concern be taken as constructive.

Published
2017

15. Prevalence of and interventions for sarcopenia in ageing adults: a systematic review. Report of the International Sarcopenia Initiative (EWGSOP and IWGS)

Author

Cruz-Jentoft, A. J., primary, Landi, F., additional, Schneider, S. M., additional, Zuniga, C., additional, Arai, H., additional, Boirie, Y., additional, Chen, L.-K., additional, Fielding, R. A., additional, Martin, F. C., additional, Michel, J.-P., additional, Sieber, C., additional, Stout, J. R., additional, Studenski, S. A., additional, Vellas, B., additional, Woo, J., additional, Zamboni, M., additional, and Cederholm, T., additional

Published
2014
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22. Dual-Energy X-Ray Absorptiometry Accurately Tracks Fat-Free Mass Changes in Older Men and Women: A Four-Compartment Molecular Model Validation

Author

Moon, J R, primary, Stout, J R, additional, Smith, A E, additional, Kendall, K L, additional, Fukuda, D H, additional, Cramer, J T, additional, Rea, M L, additional, Esposito, E N, additional, Flanagan, K E, additional, Cromartie, F, additional, Wojnar, P J, additional, Johnson, S R, additional, Foley, T, additional, Price, W, additional, and Ogden, A, additional

Published
2011
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28. Characterization of the work–time relationship during cross-country ski ergometry.

Author

Fukuda, D H, Hetrick, R P, Kendall, K L, Smith-Ryan, A E, Jackson, M E, and Stout, J R

Subjects
ERGOMETRY, CROSS-country skiing, DYNAMOMETER, STROKE, STATISTICAL correlation, COEFFICIENTS (Statistics)
Abstract

The purpose of this study was to examine the validity and reliability of estimated parameters of the work–time relationship during cross-country ski ergometry using the traditional multi-trial critical power (CP) test and a 3 min ‘all-out’ test (3MT). Fourteen recreationally active male participants (mean±SD; age: 22.14 ± 2.85 yrs; height: 177.09 ± 6.57 cm; weight: 85.68 ± 13.56 kg) completed three testing visits. All testing was conducted using an upper-body ergometer (SkiErg, Concept2, Inc., Morrisville, VT). A graded exercise test was used to determined maximal oxygen uptake (VO2peak). Two separate 3MT sessions were used to determine oxygen uptake (VO23MT), end-test power (EP), work above end-test power (WEP) and end stroke rate (ESR). Additionally, three time trials completed in a single day at simulated distances of 300 m, 650 m and 1000 m were used to estimate CP, W′ and critical stroke rate (CSR). VO2peak (3.65 ± 0.50l ⋅ min−1) and VO23MT (3.59 ± 0.4 l ⋅ min−1) were not significantly different (p = 0.162). Intraclass correlation coefficients for EP, WEP and ESR were 0.809, 0.611 and 0.783, respectively. EP (148 ± 33 W) and CP (157 ± 49 W), were not significantly different between the testing methodologies (p = 0.290) and were highly correlated (r = 0.780). WEP (8.4 ± 3.0 kJ) and W′ (8.3 ± 3.0 kJ) were similar (p = 0.947) but not related (r = 0.119), while ESR (45 ± 7 spm) and CSR (47 ± 7 spm) values were not significantly different (p = 0.238) and moderately correlated (r = 0.498). The 3MT using ski ergometry was shown to produce concurrently valid results with the traditional multi-trial CP test for CP and CSR, but not W′, and elicited similar maximal oxygen uptake values when compared to a graded exercise test. [ABSTRACT FROM AUTHOR]

Published
2014
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31. AGE AND PEAK TORQUE IN YOUNG WRESTLERS 65

Author

Ebersole, K. T., primary, Housh, T. J., additional, Johnson, G. O., additional, Housh, D. J., additional, Eckerson, J. M., additional, Weir, J. P., additional, Weir, L. L., additional, and Stout, J. R., additional

Published
1996
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38. Dentin hypersensitivity and oxalates: a systematic review.

Author

Cunha-Cruz J, Stout JR, Heaton LJ, Wataha JC, for Northwest PRECEDENT, Cunha-Cruz, J, Stout, J R, Heaton, L J, Wataha, J C, and Northwest PRECEDENT

Abstract

Treatment of dentin hypersensitivity with oxalates is common, but oxalate efficacy remains unclear. Our objective was to systematically review clinical trials reporting an oxalate treatment compared with no treatment or placebo with a dentin hypersensitivity outcome. Risk-of-bias assessment and data extraction were performed independently by two reviewers. Standardized mean differences (SMD) were estimated by random-effects meta-analysis. Of 677 unique citations, 12 studies with high risk-of-bias were included. The summary SMD for 3% monohydrogen-monopotassium oxalate (n = 8 studies) was -0.71 [95% Confidence Interval: -1.48, 0.06]. Other treatments, including 30% dipotassium oxalate (n = 1), 30% dipotassium oxalate plus 3% monohydrogen monopotassium oxalate (n = 3), 6% monohydrogen monopotassium oxalate (n = 1), 6.8% ferric oxalate (n = 1), and oxalate-containing resin (n = 1), also were not statistically significantly different from placebo treatments. With the possible exception of 3% monohydrogen monopotassium oxalate, available evidence currently does not support the recommendation of dentin hypersensitivity treatment with oxalates. [ABSTRACT FROM AUTHOR]

Published
2011
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39. EFFECTS OF CREATINE SUPPLEMENTATION ON THE ONSET OF NEUROMUSCULAR FATIGUE THRESHOLD AND MUSCLE STRENGTH IN ELDERLY MEN AND WOMEN (64 - 86 YEARS).

Author

Stout, J. R., Sue Graves, B., Cramer, J. T., Goldstein, E. R., Costa, P. B., Smith, A. E., and Walter, A. A.

Subjects
CREATINE, OLDER people, FATIGUE (Physiology), NEUROMUSCULAR system, MUSCLE strength
Abstract

Objectives: This study examined the effects of 14 days of creatine supplementation on the physical working capacity at fatigue threshold (PWCFT), maximal isometric grip strength (GRIP), sit-to-stand (STS), and body weight (BW) in elderly men and women. Design: Using a double blind cross-over design, fifteen men (n = 7) and women (n = 8) (age ± SD = 74.5 ± 6.4 yrs) were randomly assigned to either the creatine (CR) (20g.d-1 during week 1 decreasing to 10g.d-1 at week 2) or Placebo (PL) group. After a 4 to 6 week washout period, the subjects were assigned the other treatment. Before (pre) and after (post) the supplementation period, participants performed a discontinuous, cycle ergometry test to determine the PWCFT. In addition, subjects performed STS, GRIP, BW test prior to and post treatment. Setting: Southeastern part of the United States. Results: Significant increases in GRIP (6.7%) and PWCvr (15.6%) from pre- to post-supplementation were found for the CR (p<0.05) treatment, but no change for the PL treatment was observed. However, no significant change (p>0.05) was noted for STS or BW for either treatment. Conclusion: These findings suggest that 14 days of CR supplementation may increase upper body grip strength and increase physical working capacity by delaying neuromuscular fatigue in the elderly men and women in this study. While more research is needed, CR supplementation may improve upper body grip strength and lower body muscle endurance which may be important for maintaining health and independent living in elderly men and women. [ABSTRACT FROM AUTHOR]

Published
2007

41. Ligand endocytosis drives receptor dissociation and activation in the Notch pathway.

Author

Parks, A L, Klueg, K M, Stout, J R, and Muskavitch, M A

Abstract

Endocytosis of the ligand delta; is required for activation of the receptor Notch during Drosophila development. The Notch extracellular domain (NotchECD) dissociates from the Notch intracellular domain (NotchICD) and is trans-endocytosed into delta;-expressing cells in wild-type imaginal discs. Reduction of dynamin-mediated endocytosis in developing eye and wing imaginal discs reduces Notch dissociation and Notch signalling. Furthermore, dynamin-mediated delta endocytosis is required for Notch trans-endocytosis in Drosophila cultured cell lines. Endocytosis-defective delta proteins fail to mediate trans-endocytosis of Notch in cultured cells, and exhibit aberrant subcellular trafficking and reduced signalling capacity in Drosophila. We suggest that endocytosis into delta-expressing cells of NotchECD bound to delta plays a critical role during activation of the Notch receptor and is required to achieve processing and dissociation of the Notch protein.

Published
2000

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