Search Results

You are looking at 1 - 8 of 8 items for

  • Author: Margaret T. Jones x
  • All content x
Clear All Modify Search
Restricted access

Margaret T. Jones and Cynthia A. Trowbridge

Restricted access

Catherine A. Hartman, Dwight M. Hartman, and Margaret T. Jones

Restricted access

Justin J. Merrigan, James J. Tufano, Michael Falzone, and Margaret T. Jones

Purpose: To identify acute effects of a single accentuated eccentric loading (AEL) repetition on subsequent back-squat kinetics and kinematics with different concentric loads. Methods: Resistance-trained men (N = 21) participated in a counterbalanced crossover design and completed 4 protocols (sets × repetitions at eccentric/concentric) as follows: AEL65, 3 × 5 at 120%/65% 1-repetition maximum (1-RM); AEL80, 3 × 3 at 120%/80% 1-RM; TRA65, 3 × 5 at 65%/65% 1-RM; and TRA80, 3 × 3 at 80%/80% 1-RM. During AEL, weight releasers disengaged from the barbell after the eccentric phase of the first repetition and remained off for the remaining repetitions. All repetitions were performed on a force plate with linear position transducers attached to the barbell, from which eccentric and concentric peak and mean velocity, force, and power were derived. Results: Eccentric peak velocity (−0.076 [0.124] m·s−1; P = .01), concentric peak force (187.8 [284.4] N; P = .01), eccentric mean power (−145.2 [62.0] W; P = .03), and eccentric peak power (−328.6 [93.7] W; P < .01) during AEL65 were significantly greater than TRA65. When collapsed across repetitions, AEL65 resulted in slower eccentric velocity and power during repetition 1 but faster eccentric and concentric velocity and power in subsequent repetitions (P ≤ .04). When comparing AEL80 with TRA80, concentric peak force (133.8 [56.9] N; P = .03), eccentric mean power (−83.57 [38.0] W; P = .04), and eccentric peak power (−242.84 [67.3] W; P < .01) were enhanced. Conclusions: Including a single supramaximal eccentric phase of 120% 1-RM increased subsequent velocity and power with concentric loads of 65% 1-RM, but not 80% 1-RM. Therefore, AEL is sensitive to the magnitude of concentric loads, which requires a large relative difference to the eccentric load, and weight releasers may not need to be reloaded to induce performance enhancement.

Restricted access

Adam Ayash and Margaret T. Jones

Edited by Trent Nessler

Restricted access

Justin J. Merrigan, James J. Tufano, Jonathan M. Oliver, Jason B. White, Jennifer B. Fields, and Margaret T. Jones

Purpose: To examine rest redistribution (RR) effects on back squat kinetics and kinematics in resistance-trained women. Methods: Twelve women from strength and college sports (5.0 [2.2] y training history) participated in the randomized crossover design study with 72 hours between sessions (3 total). Participants completed 4 sets of 10 repetitions using traditional sets (120-s interset rest) and RR (30-s intraset rest in the middle of each set; 90-s interset rest) with 70% of their 1-repetition maximum. Kinetics and kinematics were sampled via force plate and 4 linear position transducers. The greatest value of repetitions 1 to 3 (peak repetition) was used to calculate percentage loss, [(repetition 10–peak repetition)/(peak repetition) × 100], and maintenance, {100–[(set mean–peak repetition)/(peak repetition)] × 100}, of velocity and power for each set. Repeated-measures analysis of variance was used for analyses (P < .05). Results: Mean and peak force did not differ between conditions. A condition × repetition interaction existed for peak power (P = .049) but not for peak velocity (P = .110). Peak power was greater in repetitions 7 to 9 (P < .05; d = 1.12–1.27) during RR. The percentage loss of velocity (95% confidence interval, –0.22% to –7.22%; P = .039) and power (95% confidence interval, –1.53% to –7.87%; P = .008) were reduced in RR. Mean velocity maintenance of sets 3 (P = .036; d = 1.90) and 4 (P = .015; d = 2.30) and mean power maintenance of set 4 (P = .006; d = 2.65) were greater in RR. Conclusion: By redistributing a portion of long interset rest into the middle of a set, velocity and power were better maintained. Therefore, redistributing rest may be beneficial for reducing fatigue in resistance-trained women.

Restricted access

Stephen Magness, Jatin P. Ambegaonkar, Margaret T. Jones, and Shane V. Caswell

Edited by Monique Mokha

Restricted access

Jason D. Stone, Adam C. King, Shiho Goto, John D. Mata, Joseph Hannon, James C. Garrison, James Bothwell, Andrew R. Jagim, Margaret T. Jones, and Jonathan M. Oliver

Purpose: To provide a joint-level analysis of traditional (TS) and cluster (CS) set structure during the back-squat exercise. Methods: Eight men (24 [3] y, 177.3 [7.9] cm, 82.7 [11.0] kg, 11.9 [3.5] % body fat, and 150.3 [23.0] kg 1-repetition maximum [1RM]) performed the back-squat exercise (80%1RM) using TS (4 × 6, 2-min interset rest) and CS (4 × [2 × 3], 30-s intraset rest, 90-s interset rest), randomly. Lower-limb kinematics were collected by motion capture, as well as kinetic data by bilateral force platforms. Results: CS attenuated the loss in mean power (TS −21.6% [3.9%]; CS −12.4% [7.5%]; P = .042), although no differences in gross movement pattern (sagittal-plane joint angles) within and between conditions were observed (P ≥ .05). However, joint power produced at the hip increased from repetition (REP) 1 through REP 6 during TS, while a decrease was noted at the knee. A similar pattern was observed in the CS condition but was limited to the hip. Joint power produced at the hip increased from REP 1 through REP 3 but returned to REP 1 values before a similar increase through REP 6, resulting in differences between conditions (REP 4, P = .018; REP 5, P = .022). Conclusions: Sagittal-plane joint angles did not change in either condition, although CS elicited greater power. Differing joint power contributions (hip and knee) suggest potential central mechanism that may contribute to enhanced power output during CS and warrant further study. Practitioners should consider incorporating CS into training to promote greater power adaptations and to mitigate fatigue.

Restricted access

Cristina M. Caperchione, Sean Stolp, Joan L. Bottorff, John L. Oliffe, Steven T. Johnson, Cherisse Seaton, Paul Sharp, Margaret Jones-Bricker, Sonia Lamont, Sally Errey, Theresa Healy, Kerensa Medhurst, Holly Christian, and Megan Klitch

Background:

The purpose of this study was to examine changes in physical activity and healthy eating knowledge and behaviors associated with the level of exposure to POWERPLAY, a men-centered workplace health promotion program.

Methods:

This study is based on a quasi-experimental prepost design. Using a computer assisted telephone interview survey, data regarding program exposure and physical activity and health eating knowledge and behaviors were collected from men (N = 103) in 4 workplaces.

Results:

Exposure scores were calculated and participants were categorized as having low (n = 54) or high exposure (n = 49) to POWERPLAY. Compared with the low exposure group, those reporting high exposure scored significantly higher on physical activity knowledge (F (1, 99) =14.17, P < .001, eta2 = .125) and health eating knowledge (F (1, 99) =14.37, P = .001, eta2 = .111). The high exposure group also reported significantly more minutes walked place to place (F (2, 206) = 3.91, P = .022, eta2 = .037) and on minutes walked for leisure (F (2, 230) = 3.08, P = .048, eta2 = .026).

Conclusions:

POWERPLAY shows significant promise as a workplace health promotion approach and may have an even greater impact when program exposure is augmented with environmental and policy changes.