scholarly journals Prediction of One Repetition Maximum Using Reference Minimum Velocity Threshold Values in Young and Middle-Aged Resistance-Trained Males

2021 ◽  
Vol 11 (5) ◽  
pp. 71
Author(s):  
John F. T. Fernandes ◽  
Amelia F. Dingley ◽  
Amador Garcia-Ramos ◽  
Alejandro Perez-Castilla ◽  
James J. Tufano ◽  
...  
Keyword(s):  
Bench Press ◽  
Absolute Error ◽  
Young Group ◽  
Middle Aged ◽  
Repetition Maximum ◽  
Back Squat ◽  
Velocity Threshold ◽  
Low Load ◽  
The Absolute ◽  
Minimum Velocity

Background: This study determined the accuracy of different velocity-based methods when predicting one-repetition maximum (1RM) in young and middle-aged resistance-trained males. Methods: Two days after maximal strength testing, 20 young (age 21.0 ± 1.6 years) and 20 middle-aged (age 42.6 ± 6.7 years) resistance-trained males completed three repetitions of bench press, back squat, and bent-over-row at loads corresponding to 20–80% 1RM. Using reference minimum velocity threshold (MVT) values, the 1RM was estimated from the load-velocity relationships through multiple (20, 30, 40, 50, 60, 70, and 80% 1RM), two-point (20 and 80% 1RM), high-load (60 and 80% 1RM) and low-load (20 and 40% 1RM) methods for each group. Results: Despite most prediction methods demonstrating acceptable correlations (r = 0.55 to 0.96), the absolute errors for young and middle-aged groups were generally moderate to high for bench press (absolute errors = 8.2 to 14.2% and 8.6 to 20.4%, respectively) and bent-over-row (absolute error = 14.9 to 19.9% and 8.6 to 18.2%, respectively). For squats, the absolute errors were lower in the young group (5.7 to 13.4%) than the middle-aged group (13.2 to 17.0%) but still unacceptable. Conclusion: These findings suggest that reference MVTs cannot accurately predict the 1RM in these populations. Therefore, practitioners need to directly assess 1RM.

Low-volume acute multi-joint resistance exercise elicits a circulating brain-derived neurotrophic factor response but not a cathepsin B response in well-trained men

2020 ◽  
Vol 45 (12) ◽  
pp. 1332-1338
Author(s):  
Trevor K. Johnson ◽  
Daniel J. Belcher ◽  
Colby A. Sousa ◽  
Joseph P. Carzoli ◽  
Nishant P. Visavadiya ◽  
...  
Keyword(s):  
Neurotrophic Factor ◽  
Cathepsin B ◽  
Bench Press ◽  
Brain Derived Neurotrophic Factor ◽  
Time Effect ◽  
Repetition Maximum ◽  
Back Squat ◽  
Joint Resistance ◽  
Resistance Exercises ◽  
Low Volume

This study examined if acute multi-joint resistance exercises (RE; back squat, bench press, and deadlift) to volitional failure elicited a postexercise increase in the circulating response of biomarkers associated with neuroprotection. Thirteen males (age: 24.5 ± 3.8 years, body mass: 84.01 ± 15.44 kg, height: 173.43 ± 8.57 cm, training age: 7.1 ± 4.2 years) performed 4 sets to failure at 80% of a 1-repetition maximum on the squat, bench press, and deadlift in successive weeks. The measured biomarkers were brain-derived neurotrophic factor (BDNF), insulin-like growth factor 1 (IGF-1), cathepsin B (CatB), and interleukin 6 (IL-6). Biomarkers were assessed immediately before and 10-min after exercise. There was a main time effect (pre-exercise: 24.00 ± 0.61 to postexercise: 27.38 ± 0.48 ng/mL; p < 0.01) for BDNF with increases in the deadlift (p = 0.01) and bench press (p = 0.01) conditions, but not in the squat condition (p = 0.21). There was a main time effect (pre-exercise: 0.87 ± 0.16 to postexercise: 2.03 ± 0.32 pg/mL; p < 0.01) for IL-6 with a significant increase in the squat (p < 0.01), but not the bench press (p = 0.88) and deadlift conditions (p = 0.24). No main time effect was observed for either CatB (p = 0.62) or IGF-1 (p = 0.56). In summary, acute multi-joint RE increases circulating BDNF. Further, this investigation is the first to report the lack of a transient change of CatB to an acute RE protocol. Novelty Low-volume RE to failure can increase BDNF. Resistance training does not confer an acute Cat B response.

scholarly journals The role of volume-load in strength and absolute endurance adaptations in adolescent’s performing high- or low-load resistance training

2017 ◽  
Vol 42 (2) ◽  
pp. 193-201 ◽  
Author(s):  
James Steele ◽  
James P. Fisher ◽  
Ari R. Assunção ◽  
Martim Bottaro ◽  
Paulo Gentil
Keyword(s):  
Resistance Training ◽  
Bench Press ◽  
Load Resistance ◽  
Effect Sizes ◽  
Group Differences ◽  
Muscular Endurance ◽  
Repetition Maximum ◽  
Volume Load ◽  
Low Load

This study compared high- (HL) and low-load (LL) resistance training (RT) on strength, absolute endurance, volume-load, and their relationships in untrained adolescents. Thirty-three untrained adolescents of both sexes (males, n = 17; females, n = 16; 14 ± 1 years) were randomly assigned into either (i) HL (n = 17): performing 3 sets of 4–6 repetitions to momentary concentric failure; or (ii) LL (n = 16): performing 2 sets of 12–15 repetitions to momentary concentric failure. RT was performed for 2×/week for 9 weeks. Change in maximum strength (1 repetition maximum) and absolute muscular endurance for barbell bench press was assessed. Weekly volume-load was calculated as sets (n) × repetitions (n) × load (kg). Ninety-five percent confidence intervals (CIs) revealed that both groups significantly increased in strength and absolute endurance with large effect sizes (d = 1.51–1.66). There were no between-group differences for change in strength or absolute endurance. Ninety-five percent CIs revealed that both groups significantly increased in weekly volume-load with large effect sizes (HL = 1.66, LL = 1.02). There were no between-group differences for change in volume-load though average weekly volume-load was significantly greater for LL (p < 0.001). Significant Pearson’s correlations were found for the HL group between average weekly volume-load and both strength (r = 0.650, p = 0.005) and absolute endurance (r = 0.552, p = 0.022) increases. Strength and absolute endurance increases do not differ between HL and LL conditions in adolescents when performed to momentary concentric failure. Under HL conditions greater weekly volume-load is associated with greater strength and absolute endurance increases.

scholarly journals Group versus Individualised Minimum Velocity Thresholds in the Prediction of Maximal Strength in Trained Female Athletes

2020 ◽  
Vol 17 (21) ◽  
pp. 7811
Author(s):  
Elias J. G. Caven ◽  
Tom J. E. Bryan ◽  
Amelia F. Dingley ◽  
Benjamin Drury ◽  
Amador Garcia-Ramos ◽  
...  
Keyword(s):  
Bench Press ◽  
Female Athletes ◽  
Group Versus ◽  
Absolute Error ◽  
Point Method ◽  
Multiple Point ◽  
Loading Test ◽  
Mean Velocity ◽  
Velocity Relationship ◽  
Minimum Velocity

This study examined the accuracy of different velocity-based methods in the prediction of bench press and squat one-repetition maximum (1RM) in female athletes. Seventeen trained females (age 17.8 ± 1.3 years) performed an incremental loading test to 1RM on bench press and squat with the mean velocity being recorded. The 1RM was estimated from the load–velocity relationship using the multiple- (8 loads) and two-point (2 loads) methods and group and individual minimum velocity thresholds (MVT). No significant effect of method, MVT or interaction was observed for the two exercises (p > 0.05). For bench press and squat, all prediction methods demonstrated very large to nearly perfect correlations with respect to the actual 1RM (r range = 0.76 to 0.97). The absolute error (range = 2.1 to 3.8 kg) for bench press demonstrated low errors that were independent of the method and MVT used. For squat, the favorable group MVT errors for the multiple- and two-point methods (absolute error = 7.8 and 9.7 kg, respectively) were greater than the individual MVT errors (absolute error = 4.9 and 6.3 kg, respectively). The 1RM can be accurately predicted from the load–velocity relationship in trained females, with the two-point method offering a quick and less fatiguing alternative to the multiple-point method.

scholarly journals Perception of bar velocity in resistance training: Accuracy levels within and between exercises

2020 ◽  
Author(s):  
Mahmood Sindiani ◽  
Amit Lazarus ◽  
Antonio Dello Iacono ◽  
Israel Halperin
Keyword(s):  
Resistance Training ◽  
Bench Press ◽  
Absolute Error ◽  
Percentage Points ◽  
Linear Encoder ◽  
The Absolute ◽  
The Difference ◽  
Velocity Measuring ◽  
Bar Velocity ◽  
Tracking Devices

Velocity-based training is a method used to monitor resistance-training programs based on repetition velocities measured with tracking devices. Since velocity measuring devices can be expensive and impractical, trainee’s perception of velocity (POV) may be used as a possible substitute. Here, 20 resistance-trained males first completed 1RM tests in the bench-press and squat. Then, in three counterbalanced sessions, participants completed four sets of eight repetitions in both exercises using 60%1RM (two-sessions) or 70%1RM. Starting from the second repetition, participants reported their POV of each repetition as a percentage of the first repetition. Accuracy was calculated as the difference between POV and actual-velocity measured with a linear-encoder. Two key findings emerged. First, the absolute error in both exercises was ~5.8 percentage-points in the second repetition, and it increased to 13.2 and 16.7 percentage-points by the eighth repetition, in the bench-press and squat, respectively. Second, participants were 4.2 times more likely to underestimate velocity in the squat. Given the gradual increments in the absolute error, POV may be better suited for sets of fewer repetitions (e.g., 4-5) and wider velocity-loss threshold ranges (e.g., 5-10%). Given the systematic underestimation error in the squat, a correction factor may increase POV accuracy in this exercise.

scholarly journals Reliability of the velocity achieved during the last repetition of sets to failure and its association with the velocity of the 1-repetition maximum

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8760 ◽  
Author(s):  
Amador García-Ramos ◽  
Danica Janicijevic ◽  
Jorge M. González-Hernández ◽  
Justin W.L. Keogh ◽  
Jonathon Weakley
Keyword(s):  
Bench Press ◽  
Loading Test ◽  
Repetition Maximum ◽  
Healthy Men ◽  
Velocity Threshold ◽  
Velocity Relationship ◽  
Minimal Velocity ◽  
Repetitions To Failure ◽  
Incremental Loading

Background This study aimed to determine the reliability of the velocity achieved during the last repetition of sets to failure (Vlast) and the association of Vlast with the velocity of the 1-repetition maximum (V1RM) during the paused and touch-and-go bench press (BP) exercises performed in a Smith machine. Methods A total of 96 healthy men participated in this study that consisted of two testing sessions. A single BP variant (paused BP or touch-and-go BP) was evaluated on each session in a randomized order. Each session consisted of an incremental loading test until reaching the 1RM, followed by two sets of repetitions to failure against a load ranging from 75% to 90% of 1RM. Results The reliability of Vlast was unacceptable for both BP variants (CV > 18.3%, ICC < 0.60). The correlations between V1RM and Vlast were small for the paused BP (r = 0.18) and moderate for the touch-and-go BP (r = 0.37). Conclusions Although these results suggest that Vlast could be a better indicator of the minimal velocity threshold than V1RM, the low reliability of Vlast and the similar values of Vlast for both BP variants suggest that a standard V1RM should be used to estimate the 1RM from the individualized load-velocity relationship.

Investigation of Heat Transfer for Shell-Tube Fuel-Cooled Heat Exchanger

2013 ◽  
Vol 378 ◽  
pp. 459-465
Author(s):  
Ya Guo Lu ◽  
Peng Fei Zhu
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Relative Error ◽  
Absolute Error ◽  
Heat Transfer Characteristics ◽  
Shell Side ◽  
Transfer Characteristics ◽  
Aero Engine ◽  
The Absolute

A calculate method based on ε-NTU model for heat transfer characteristics of shell-tube fuel-cooled heat exchanger of aero-engine lubrication system was built. The heat convection coefficient was obtained by a dimensionless curve (Re~StPr2/3), which was detailed introduced as well. A case study was executed at last. The absolute error of the outlet lubrication of the tube side and the shell side between the value of calculation and experiment was less than ±10°C, and the relative error was less than 6.5%. The absolute error of the heat transferred between calculation and experiment was less than ±0.9kW, and the relative error was less than 7.4%. It indicates that the mothod is available for the investigation of heat transfer characteristics of shell-tube fuel-cooled heat exchanger.

scholarly journals Comparison of MODIS and AERONET derived aerosol optical depth over the Ganga Basin, India

2005 ◽  
Vol 23 (4) ◽  
pp. 1093-1101 ◽  
Author(s):  
S. N. Tripathi ◽  
Sagnik Dey ◽  
A. Chandel ◽  
S. Srivastava ◽  
Ramesh P. Singh ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Time Window ◽  
Absolute Error ◽  
Absolute Difference ◽  
Ganga Basin ◽  
Monsoon Period ◽  
Post Monsoon ◽  
Dust Loading ◽  
The Absolute

Abstract. The Moderate Resolution Imaging Spectroradiometer (MODIS) onboard EOS Terra measures global aerosol optical depth and optical properties since 2000. MODIS aerosol products are freely available and are being used for numerous studies. In this paper, we present a comparison of aerosol optical depth (AOD) retrieved from MODIS with Aerosol Robotic Network (AERONET) data for the year 2004 over Kanpur, an industrial city lying in the Ganga Basin in the northern part of India. AOD retrieved from MODIS (τaMODIS) at 0.55µm wavelength has been compared with the AERONET derived AOD (τaAERONET), within an optimum space-time window. Although the correlation between τaMODIS and τaAERONET during the post-monsoon and winter seasons (R2~0.71) is almost equal to that during the pre-monsoon and monsoon seasons (R2~0.72), MODIS is found to overestimate AOD during the pre-monsoon and monsoon period (characterized by severe dust loading) and underestimate during the post-monsoon and winter seasons. The absolute difference between τaMODIS and τaAERONET is found to be low (0.12±0.11) during the non-dust loading season and much higher (0.4±0.2) during dust-loading seasons. The absolute error in τaMODIS is found to be about ~25% of the absolute values of τaMODIS. Our comparison shows the importance of modifying the existing MODIS algorithm during the dust-loading seasons, especially in the Ganga Basin in northern part of India.

scholarly journals Local snake fruit conservation in East Java, Indonesia: Community knowledge and appreciation

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Novita Indah ◽  
SERAFINAH INDRIYANI ◽  
ESTRI LARAS ARUMINGTYAS ◽  
RODIYATI AZRIANINGSIH
Keyword(s):  
Plant Species ◽  
Young Group ◽  
Product Diversification ◽  
Conservation Strategy ◽  
Middle Aged ◽  
Community Based ◽  
Community Knowledge ◽  
Open Questions ◽  
Community Based Conservation ◽  
Fruit Cultivation

Abstract. Indah NK, Indriyani S, Arumingtyas EL, Azrianingsih R. 2021. Local snake fruit conservation in East Java, Indonesia: Community knowledge and appreciation. Biodiversitas 22: 416-423. The community-based conservation of plant species diversity by variety of utility is an effective method for preserving local plants. Salak or the ‘snake fruit’ from East Java is an important fruit plant species in East Java. However, recent dramatic decline in its production and consumption occurred due to land-use change of plantation into resident or settlement areas. This study aims to analyze the value of local knowledge and appreciation and discusses the conservation strategy to cope with the situation. This descriptive research adopted 328 respondents from 10 local and introduced snake fruit cultivation areas in East Java. Respondents were divided into four age categories: young (17-30 years), adults (30-45 years), middle-aged (45-60 years), and old (>60 years). The questioner consisted of closed and open questions about knowledge (9 questions) and appreciation (13 questions). There were variations in the level of knowledge and appreciation between locations and ages. The highest appreciation about snake fruit utilization was shown by the middle-aged group (85.53% and 75% respectively) based on the age group. In comparison, the lowest scores were shown in the young group (79.82% and 59.80% respectively). The points that support appreciation such as benefits  and value of snake fruit for societal support. Based on the snake fruit cultivation area, the highest score for knowledge and appreciation of its value was found in Bojonegoro (98.1% and 87.01% respectively) while these were the lowest in Trenggalek (68.0% and 57.10% respectively). Appreciation supports community-based conservation through snake fruit festivals, product diversification i.e. making processed foods, and its use in religious ceremonies.

scholarly journals Characteristic Movement of the Ribs, Thoracic Vertebrae while Elevating the Upper Limbs - Influences of Age and Gender on Movements

2019 ◽  
Vol 13 (1) ◽  
pp. 170-176
Author(s):  
Hisayoshi Tachihara ◽  
Junichiro Hamada
Keyword(s):  
Young Group ◽  
Thoracic Vertebrae ◽  
Middle Aged ◽  
Age And Gender ◽  
Aged Group ◽  
Age Related ◽  
Significant Difference ◽  
Shoulder Disorders ◽  
Arm Elevation ◽  
And Gender

Background: The rib cage, such as the thoracic spine and ribs, influences glenohumeral mobility and the development of shoulder disorders. Objective: To evaluate movements of the ribs, thoracic vertebrae during bilateral arm elevation and to clarify the characteristic influences of age and gender. Methods: Subjects comprised 33 healthy individuals divided into a young group (10 males, 7 females; mean age, 25 years) and a middle-aged group (8 males, 8 females; mean age, 52 years). Chest CT was performed with two arm positions: arms hanging downwards; and arms elevated at 160°. Images were three-dimensionally reconstructed to evaluate rib movement, extension angle of thoracic vertebrae. Results: Maximal movement was observed at the fifth rib, and rib movement decreased with increasing distance from the fifth rib in both the groups. In males, movement of the second to fourth ribs was smaller in the middle-aged group than in the young group (p < 0.05). Movement of the first to ninth ribs was smaller in females than in males (p < 0.05). No significant difference in the extension angle of the thoracic vertebrae was found. Conclusion: Fifth rib movement is the largest among all ribs during bilateral arm elevation. Reduction of upper rib movement initially arises as an age-related degradation in males. Women exhibit less rib movement during bilateral arm elevation.

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