Search Results

You are looking at 1 - 10 of 586 items for :

  • Physical Education and Coaching x
  • Refine by Access: All Content x
Clear All
Restricted access

Effect of Absolute and Relative Loading on Muscle Activity During Stable and Unstable Squatting

Jeffrey M. McBride, Tony R. Larkin, Andrea M. Dayne, Tracie L. Haines, and Tyler J. Kirby

Purpose:

The purpose of this investigation was to determine the effect of stable and unstable conditions on one repetition maximum strength and muscle activity during dynamic squatting using absolute and relative loading.

Methods:

Ten recreationally weight-trained males participated in this study (age = 24.1 ± 2.0 y, height = 178.0 ± 5.6 cm, body mass = 83.7 ± 13.4 kg, 1RM/body mass = 1.53 ± 0.31), which involved two laboratory sessions separated by 1 wk. Linear position transducers were used to track bar displacement while subjects stood on a force plate for all trials. Vastus lateralis (VL), biceps femoris (BF) and erector spinae (L1) muscle activity (average integrated EMG [IEMG]) was also recorded during all trials. During the frst session subjects complete a one repetition maximum test in a stable dynamic squat (S1RM = 128.0 ± 31.4 kg) and an unstable dynamic squat (U1RM = 83.8 ± 17.3 kg) in a randomized order with a 30-min rest period between conditions. The second session consisted of the performance of three trials each for 12 different conditions (unstable and stable squats using three different absolute loads [six conditions] and unstable and stable squats using three different relative loads [six conditions]).

Results:

Results revealed a statistically significant difference between S1RM and U1RM values (P < .05). The stable trials resulted in the same or a significantly higher value for VL, BF and L1 muscle activity in comparison with the unstable trials for all twelve conditions.

Conclusions:

Unstable squatting is of equal or less (depending on the loading condition) benefit to improving or maximizing muscle activity during resistance exercise.

Restricted access

An Assessment of the Validity of the Remote Food Photography Method (Termed Snap-N-Send) in Experienced and Inexperienced Sport Nutritionists

Reuben G. Stables, Andreas M. Kasper, S. Andy Sparks, James P. Morton, and Graeme L. Close

methods of dietary assessment. Such estimates of validity should therefore be taken into account when utilizing this method, alongside the requirement to use multiple coders when performing a dietary analysis of athletic populations. Acknowledgments The study was designed by R.G. Stables, A.M. Kasper, J

Restricted access

Acquiring a Stable Estimate of Physical Activity in Adults With Visual Impairment

Elizabeth A. Holbrook, Minsoo Kang, and Don W. Morgan

As a first step toward the development of adapted physical activity (PA) programs for adults with visual impairment (VI), the purpose of this study was to determine the time frame needed to reliably estimate weekly PA in adults with VI. Thirty-three adults with VI completed 7 days of pedometer-based PA assessment. Generalizability theory analyses were conducted to quantify sources of variance within the PA estimate and determine the appropriate number of days of PA monitoring needed for the total sample and for participants with mild-to-moderate and severe VI. A single-facet, crossed design was employed including participants and days. Participants and days correspondingly accounted for 33–55% and 0–3% of the total variance in PA. While a reliable account of PA was obtained for the total sample over a 6-day period, shorter (4-day) and longer (9-day) periods were required for persons with mild-to-moderate and severe VI, respectively.

Restricted access

Reliability of Urinary Dehydration Markers in Elite Youth Boxers

Damir Zubac, Drazen Cular, and Uros Marusic

that urinary dehydration markers (both field and laboratory) exhibit large variability and inconsistency (U OSM increased by ∼16% over a 7-d period) in elite youth boxers, regardless of stable body mass or adequate macronutrient intake. 11 Sing and Peters 12 reported poor correlation between

Restricted access

Reconceptualizing Teacher Identity: Teachers’ Becoming in the Dynamic Complexity of Teaching Situations

Romana Puchegger and Toni Bruce

from stable process–product discourse toward ideas of teaching and becoming teacher that acknowledge the multiple, complex, and ever‐changing factors that intersect to inform each teaching occurrence. In this argument, we follow educators such as Cochran-Smith, Ell, Ludlow, Grudnoff, and Aitken

Restricted access

Measuring Perceived Transfer of Responsibility Learning From Physical Education: Initial Validation of the Transfer of Responsibility Questionnaire

Paul M. Wright, K. Andrew R. Richards, Jennifer M. Jacobs, and Michael A. Hemphill

) developing items to be included on the ToRQ, (b) identifying a stable factor structure for the ToRQ using exploratory factor analysis (EFA), (c) confirming the factor structure through confirmatory factor analysis (CFA) using a separate participant sample, and (d) examining the extent to which the ToRQ correlates

Restricted access

Total Energy Expenditure, Physical Activity Level, and Water Turnover of Collegiate Dinghy Sailors in a Training Camp

Hiroyuki Sagayama, Makiko Toguchi, Jun Yasukata, Kazunari Yonaha, Yasuki Higaki, and Hiroaki Tanaka

, incorporating a special silicone gasket for the best possible seal, and were wrapped tightly with Parafilm M (Bemis Co., Inc., Oshkosh, WI). We analyzed the urine samples with isotope ratio mass spectrometry (Hydra 20-20 Stable Isotope Mass Spectrometer; SerCon Ltd., Crewe, United Kingdom). The 18 O and 2 H

Restricted access

Relationships Among PlayerLoad, High-Intensity Intermittent Running Ability, and Injury Risk in Professional Rugby League Players

Billy T. Hulin, Tim J. Gabbett, Nathan J. Pickworth, Rich D. Johnston, and David G. Jenkins

Associations Changes in HR submax were investigated relative to each individual’s performance over the duration of the study and compared with injury risk. A within-individual z score was calculated for HR submax before being sorted into 3 categories: decrease ( z score, <−0.5), stable ( z score, −0.5 to

Restricted access

Sex Differences in World-Record Performance: The Influence of Sport Discipline and Competition Duration

Øyvind Sandbakk, Guro Strøm Solli, and Hans-Christer Holmberg

and freestyle swimming were approximately 10% to 12%. However, the difference in men’s and women’s world records for 500-m speed skating was reduced to 7%. For all Olympic running events longer than 100 m, the sex differences in world records are relatively stable at 10% to 12%, without any clear

Restricted access

Fortune Favors the Brave: Tactical Behaviors in the Middle-Distance Running Events at the 2017 IAAF World Championships

Arturo Casado and Andrew Renfree

percentage of AQ already in qualifying positions were 32.1%, 42.9%, and 65.7% at 400 m, 800 m, and 1200 m. Race positions remained more stable throughout 800-m races (Figure  1 ) than through the 1500-m races which visual inspection of data suggests were characterized by a greater degree of positional change