Matching Items (5)

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A Comparison of the Effects of Two Warm- Up Protocols on Strength and Power in College- Aged Females

Description

The following study compared the effects of acute static stretching (SS) and whole body vibration (WBV) protocols on strength and power in college-aged recreationally active females. Ten active, Arizona State

The following study compared the effects of acute static stretching (SS) and whole body vibration (WBV) protocols on strength and power in college-aged recreationally active females. Ten active, Arizona State University females participated in the study after providing informed consent and filling out a survey to determine their health status and physical activity level. Participants took part in the study over two days, each day starting with a standardized cycling protocol, followed by random assignment to either a static stretching or whole body vibration warm-up condition. Whichever protocol they did not complete during the first session, they completed during the second session. After the warm-up protocol, vertical hang time and vertical jump were used to test leg power, and 1- RM bench press, and 1- RM leg press were used to evaluate the participants’ upper and lower body strength, respectively. Multiple t-tests were conducted for each sports performance test conducted: vertical hang time, vertical jump, bench press, and leg press. Strength and power, as assessed in this sample, were not significantly different based on warm-up protocol. T-tests comparing the effects of two warm-up techniques revealed that there were no significant differences in the leg power scores for vertical hang time (p ≤0.86) (effect size = 0), or vertical jump height (p =1) (effect size = 0). Similarly, there were no significant differences in bench press (p ≤0.08) (effect size = 0.38), and leg press (p ≤0.29) (effect size = 0.31), although effect sizes were moderate. Because of the medium effect sizes for leg press (0.31) and bench press (0.38), it is possible that WBV can facilitate greater strength gains in female college students, but more subjects are needed to further evaluate this finding. Given that leg power was not different based on warm-up technique, it is possible that static stretching for less than 30 seconds did not impede power in these active females. Clearly, more research needs to be performed on the effectiveness of the vibration platform comparing additional bouts of duration and frequency in active and athletic college-aged females.

Contributors

Agent

Created

Date Created
  • 2017-12

Ideal Weightlifting Volume and Frequency for the Male Lifter

Description

For my Honor’s Project for Barrett the Honors College, I chose to research and develop an
application on the topic of Ideal Weightlifting Volume and Frequency for The Male Lifter.

For my Honor’s Project for Barrett the Honors College, I chose to research and develop an
application on the topic of Ideal Weightlifting Volume and Frequency for The Male Lifter. The
reason I decided to center my project around this topic is due to the plethora of information
available on this subject matter. However, I was more driven to pursue this subject matter due to
the lack of implementation and usage of all the relevant information and case studies offered to
us through the means of online journals, abstracts, reports, etc.
The application will be programmed using the software known as Android Studio. Inside
Android Studio, the programming language that will be utilized is Java. The goal for this
application is to gather information from the user, and with that information, create a conducive
weekly weightlifting regiment based on the wants and needs of the user. Furthermore, the
application will only create programs on a week to week basis, thus encouraging the user to
dabble with different preferences each week. Outputting the program on a week-to-week basis is
an integral logic of this program because it is my belief that if the user is given the privilege to
change their programming on a weekly basis this will allow for flexibility, adaptability, and the
pursuance of short-term goals, which is much more tangible in the onslaught of obtaining a goal.
When browsing through the app store or the internet, it is incredibly difficult to find online
programs that utilize research and scientific credibility. Many of these programs and trainers
offer quick results that are flashy and trendy, however lack any real qualitative reinforcement.
Thus, it is my mission, with my application, to create a program that is intuitive for the user, as
well as to provide scientific programming with proper citation of case studies and reports
conducted by educated individuals.

Contributors

Agent

Created

Date Created
  • 2019-05

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Dietary protein quality, muscle mass, and strength in vegetarian athletes

Description

Vegetarian diets can provide an abundance of nutrients when planned with care. However, research suggests that vegetarian diets may have lower protein quality than omnivore diets. Current protein recommendations assume

Vegetarian diets can provide an abundance of nutrients when planned with care. However, research suggests that vegetarian diets may have lower protein quality than omnivore diets. Current protein recommendations assume that vegetarians obtain a majority of their protein from animal products, like dairy and eggs. Studies have shown that this assumption may not be valid. The recommended dietary allowance (RDA) may not be adequate in vegetarian populations with high protein requirements. The purpose of this study is to analyze dietary protein quality using the DIAAS (Digestible Indispensable Amino Acid Score) method in both vegetarian and omnivore endurance athletes. 38 omnivores and 22 vegetarians submitted 7-day food records which were assessed using nutrition analysis software (Food Processor, ESHA Research, Salem, OR, USA). Dietary intake data was used to calculate DIAAS and determine the amount of available dietary protein in subject diets. Dietary data was compared with the subjects’ lean body mass (obtained using DEXA scan technology), and strength (quantified using peak torque of leg extension and flexion using an isokinetic dynamometer). Statistical analyses revealed significantly higher available protein intake in the omnivore athletes (p<.001). There were significant correlations between available protein intake and strength (p=.016) and available protein intake and lean body mass (p<.001). Omnivore subjects had higher lean body mass than vegetarian subjects (p=.011). These results suggest that vegetarian athletes may benefit from higher overall protein intakes to make up for lower dietary protein quality.

Contributors

Agent

Created

Date Created
  • 2017

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Effects of dynamic material strength on hydrodynamic instability and damage evolution in shock loaded copper

Description

Characterization and modeling of deformation and failure in metallic materials under extreme conditions, such as the high loads and strain rates found under shock loading due to explosive detonation and

Characterization and modeling of deformation and failure in metallic materials under extreme conditions, such as the high loads and strain rates found under shock loading due to explosive detonation and high velocity-impacts, are extremely important for a wide variety of military and industrial applications. When a shock wave causes stress in a material that exceeds the elastic limit, plasticity and eventually spallation occur in the material. The process of spall fracture, which in ductile materials stems from strain localization, void nucleation, growth and coalescence, can be caused by microstructural heterogeneity. The analysis of void nucleation performed from a microstructurally explicit simulation of a spall damage evolution in a multicrystalline copper indicated triple junctions as the preferred sites for incipient damage nucleation revealing 75% of them with at least two grain boundaries with misorientation angle between 20-55°. The analysis suggested the nature of the boundaries connecting at a triple junction is an indicator of their tendency to localize spall damage. The results also showed that damage propagated preferentially into one of the high angle boundaries after voids nucleate at triple junctions. Recently the Rayleigh-Taylor Instability (RTI) and the Richtmyer-Meshkov Instability (RMI) have been used to deduce dynamic material strength at very high pressures and strain rates. The RMI is used in this work since it allows using precise diagnostics such as Transient Imaging Displacement Interferometry (TIDI) due to its slower linear growth rate. The Preston-Tonks-Wallace (PTW) model is used to study the effects of dynamic strength on the behavior of samples with a fed-thru RMI, induced via direct laser drive on a perturbed surface, on stability of the shock front and the dynamic evolution of the amplitudes and velocities of the perturbation imprinted on the back (flat) surface by the perturbed shock front. Simulation results clearly showed that the amplitude of the hydrodynamic instability increases with a decrease in strength and vice versa and that the amplitude of the perturbed shock front produced by the fed-thru RMI is also affected by strength in the same way, which provides an alternative to amplitude measurements to study strength effects under dynamic conditions. Simulation results also indicate the presence of second harmonics in the surface perturbation after a certain time, which were also affected by the material strength.

Contributors

Agent

Created

Date Created
  • 2016

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Comparison of concentric and eccentric bench press

Description

Eccentric muscle action (ECC) occurs when the force exerted by a working muscle is less than that of an outside resistance. This is characterized by muscle lengthening, despite actin-myosin crossbridge

Eccentric muscle action (ECC) occurs when the force exerted by a working muscle is less than that of an outside resistance. This is characterized by muscle lengthening, despite actin-myosin crossbridge formation. Research has indicated that muscles acting eccentrically are capable of producing more force when compared to muscles acting concentrically. Further, research has shown ECC muscle actions may have different fatigue patterns that CON actions. The purpose of this study was to determine if a) ECC bench press yields greater strength than concentric (CON) as measured by one-repetition maximum (1RM), b) there is a difference between the number of repetitions that can be completed concentrically and eccentrically under the same relative intensities of 1RM (90%, 80%, 70%, 60%), c) a prediction model may be able to predict ECC 1RM from CON 1RM or CON repetitions to fatigue. For this study, 30 healthy males (age = 24.63 + 5.6 years) were tested for 1RM in CON and ECC bench press, as well as the number of repetitions they were able to complete at various intensities of mode-specific 1RM. A mechanical hoist was affixed to a gantry crane and placed over a standard weightlifting bench. The hoist was connected to 45lb plates that were loaded on a standard barbell, which allowed for mechanical raising and lowering of the barbell. For CON repetitions, the weight was mechanically lowered to the chest and the participant pressed it up. For ECC repetitions, the weight was mechanically raised and the participant lowered it. Paired t-tests showed that ECC 1RM was significantly (p < 0.05) greater than CON 1RM (ECC =255.17 + 68.37lbs, CON = 205.83 + 58.43lbs). There was a significant difference (p < 0.05) between the number of repetitions completed at 90% 1RM (CON = 4.57 + 2.21 repetitions, ECC = 7.67 + 3.24 repetitions). There were no differences in repetitions completed at any other intensity 1RM. CON 1RM and the number of repetitions completed with two different absolute loads (130-150lbs and 155-175lbs) concentrically and eccentrically were valid predictors of ECC 1RM. These data indicate that ECC actions yield increased force capabilities than CON actions, there is no difference in the rate of the fatigue, and ECC 1RM may be predicted from various CON tests.

Contributors

Agent

Created

Date Created
  • 2013