- Thread:
- The Effects of Lower Extremity Muscle Activation and Passive Range of Motion on Single Leg Squat Performance
- Post:
- The Effects of Lower Extremity Muscle Activation and Passive Range of Motion on Single Leg Squat Performance
- Author:
Michael Cisneros
- Posted Date:
- October 6, 2013 7:37 PM
- Status:
- Published
Michael Cisneros
October 6, 2013
Advanced Nutrition
The Effects of Lower Extremity Muscle Activation and Passive Range of Motion on Single Leg Squat Performance
Reference
Mauntel, Timothy C., Rebecca L. Begalle, Tyler R. Cram, Barnett S. Frank, Christoper J. Hearth, Troy Blackburn, and Darin A. Paua. "The Effects of Lower Extremity Muscle Activation and Passive Range of Motion on Single Leg Squat Performance." Journal of Strength and Conditioning Research 27.7 (2013): 1813-823. Web. 6 Oct. 2013.
Purpose of the Study
The purpose of this study was to compare the LE muscle activation and PROM between subjects who display dynamic knee valgus and those who do not during an SLS. The authors hypothesized that individuals who displayed MKD during the SLS would demonstrate greater LE muscle activity and lesser PROM compared with those who maintained a neutral knee alignment.
Methods and Materials
Before data collection, all subjects underwent a screening session, which allowed the researchers to determine each subject's group assignment (control or MKD). During the data collection session, LE PROM was measured for each subject. Joint angles for PROM were measured using a digital inclinometer or standard goniometer. Surface EMG was used to record LE muscle activity for each of the muscles examined in this study during 5 SLS trials.
Results
All MANOVA statistical analyses examining group differences for EMG amplitude, EMG coactivation ratios, and PROM measurements met the assumptions for Homogeneity of Covariance. For statistically significant MANOVAs, follow-up one-way ANOVA analyses were run to examine the main effect for group for the EMG coactivation ratios and PROM measurements; all follow-up ANOVAs met the assumptions for Homogeneity of Variance. The findings of this study indicate that dorsiflexion range of motion measurements are lesser in subjects displaying MKD compared with those who do not. The authors believe this limited dorsiflexion may result in compensatory movements in the ankle and lower leg, resulting in foot pronation and tibial internal rotation. Greater levels of hip adductor activity without an associated increase in gluteus medius and/or gluteus maximus activity may increase femoral adduction and internal rotation; potentially increasing MKD during dynamic tasks. MKD is suggested to be a biomechanical factor associated with ACL injury, MCL injury, and PFPS. Rehabilitation and injury prevention programs that increase dorsiflexion range of motion, decrease hip adductor activity, and increase hip abductor and external rotator activity may decrease the incidence of these injuries.
Critique of the Study
The sample population used for the study was all healthy and active individuals. This may have little crossover to the effect of non-contact knee injury that occurs in athletes with previous/existing lower extremity injuries. In addition, the only method used to determine possible risk of non-contact knee injury was the single leg squat at a fixed angle knee bends of 60 degrees with the dominant leg. In future studies, different methods of measurement should be used to increase precision in determining the presence of faulty biomechanics of the knee. Further study should be done utilizing bilateral body squats and single leg squats analyzed through a fuller range of motion of the knee and the effect it has for reducing non-contact knee injuries. Further, does training the 2-legged squat and 1-legged squat through a fuller range of motion help prevent medial knee deviation and decrease the risk of non-contact injury to the lower extremities? With that said, more research is needed to determine this.
Practical Application
Clinical screenings may be used by clinicians to help identify athletes at increased risk for LE injuries. These screening tools may also help identify which underlying factors contribute to the faulty movement patterns exhibited during the screening. The information gained from clinical screenings should then be used by the clinician to aid in the development of conditioning, rehabilitation, and injury prevention programs.
Specifically, the findings of this study suggest smaller Gluteal:Hip Add coactivation ratios and lesser dorsiflexion PROM in individuals displaying MKD may have important implications for knee injury prevention and rehabilitation programs. Individuals displaying smaller Gluteal:Hip Add coactivation ratios may benefit from rehabilitation exercises focused on increasing gluteus medius and gluteus maximus activation. These individuals may also benefit from inhibiting the hip adductors through stretching and inhibition techniques, such as self-myofascial release, which allow the muscle to relax to enhance stretching. Similar treatments could be used to increase gastrocnemius and soleus PROM and allow for greater ankle dorsiflexion. Ultimately, clinical screenings may aid in the development of better individualized prevention and treatment plans and decrease the incidence of noncontact knee injuries.
- Thread:
- The Effects of 8 Weeks of Whey or Rice Protein Supplementation on Body Composition and Exercise Performance
- Post:
- The Effects of 8 Weeks of Whey or Rice Protein Supplementation on Body Composition and Exercise Performance
- Author:
- John Lerma
- Posted Date:
- October 6, 2013 5:51 PM
- Status:
- Published
Research Review #2 - The Effects of 8 Weeks of Whey or Rice Protein Supplementation on Body Composition and Exercise Performance
Reference
Joy, J. M., Lowery, R. P., Wilson, J. M., Purpura, M., De Souza, E. O., Wilson, S. C., & ... Jäger, R. (2013). The effects of 8 weeks of whey or rice protein supplementation on body composition and exercise performance. Nutrition Journal, 12(1), 1-7. doi:10.1186/1475-2891-12-86
Purpose of Study
The purpose of this study was to determine if the post-exercise consumption of rice protein isolate could increase recovery and produce adequate changes in body composition as compared to equally dosed whey protein isolate.
Methods and Materials
The study consisted of a randomized, double blind protocol that consisted of individuals either given 48 grams of rice or 48 grams of whey protein isolate following an acute exercise bout (phase 1), as well as following each session in an 8 week periodized training regimen (phase 2). Direct ultrasound determined muscle mass, DEXA determined body composition, and maximal strength and power were assessed at the end of weeks 0, 4, and 8.
Twenty-four healthy males participated in this particular study.The study required that all participants stop taking nutritional supplements for three months prior to the study. It also required that all participants had a minimum of 1 year experience in resistance training, and that all had participated in resistance training at least 3 times per week for the past six months. The participants were then carefully matched by age, body mass, strength, and resistance training experience. Then participants were randomly assigned to either the rice or the whey group.
Summary of Results/Conclusion
In phase 1, there were no differences in total amount of weight lifted in either group. However, there was a significant time effect for soreness in both the RPI (0.3±0.6 to 5.6±2.2) and WPI (0.3±0.5 to 6.0±1.9) groups, with no differences between groups. There was also a significant time effect for perceived readiness scale, which decreased in both the RPI (9.1±1.5 to 5.45±1.5) and WPI (8.7±2.6 to 5.6±1.4) groups, with no differences between groups. In phase 2, there was a significant time effect for lean body mass. Lean body mass increased in both the rice (58.5±5.5 to 59.5±4.5 to 61±5.6 kg), and the whey protein (59.6±5.2 to 61.9±4.5 to 62.8±5.2 kg) conditions. There was also a significant time effect for body fat, which decreased in both groups from pre to post training.
The results of the current study suggest that differences in protein composition are less relevant when protein is consumed in large doses throughout periodized resistance training. Rice protein isolate consumption post resistance exercise decreases fat-mass and increases lean body mass, skeletal muscle hypertrophy, power and strength comparable to whey protein isolate.
Critique of the Study
The lack of a non-supplemented control group prevents us from concluding how beneficial protein supplementation is to resistance training in this study. The results are also limited by the short duration of the research conducted. Over a longer duration of time the potential differences in effects of body composition and exercise performance between groups may be more apparent. Further research should include a non-supplemented control group, and should conduct research over a longer period of time.
Practical Applications of the Study
The post-resistance exercise administration of whey and rice protein isolates both improved indices of body composition and exercise performance. From the current study, you could conclude that protein intake in higher doses post resistance exercise can improve body composition in terms of lean body mass and fat mass and athletic performance in terms of maximal strength and power despite the composition of the protein itself. However, without a non-supplemented control group it is difficult to determine just how beneficial each type of protein supplementation truly is to resistance training.
- Thread:
- RR2 Childhood Obesity- Ram Lopez
- Post:
- RR2 Childhood Obesity- Ram Lopez
- Author:
- Ramiro Lopez
- Posted Date:
- October 6, 2013 9:56 PM
- Status:
- Published
Attachment: 
RR2.docx (19.458 KB)
RR2.docx (19.458 KB)- Thread:
- Effects of carbohydrate supplementation on force output and time to exhaustion during static leg contractions superimposed with electromyostimulation
- Post:
- Effects of carbohydrate supplementation on force output and time to exhaustion during static leg contractions superimposed with electromyostimulation
- Author:
- Vickie Machen
- Posted Date:
- October 5, 2012 8:14 PM
- Status:
- Published
Research Review 2
Wax, B., Brown, S. P., Webb, H. E., & Kavazis, A. N. (2012). Effects of carbohydrate supplementation on force output and time to exhaustion during static leg contractions superimposed with electromyostimulation. Journal of Strength and Conditioning Research, 26(6), 1717-1723.
The purpose of this study was to investigate the effects of carbohydrate ingestion on force output and time exhaustion using single leg static contractions superimposed with brief periods of electromyostimulation.
Methods and Materials
The subjects consisted of six trained male subjects that participated in a randomized, counterbalanced, and double-blind study. The subjects were randomly assigned to either the placebo (n=3) or carbohydrate supplement group (n=3). The subjects of both groups ingested one gram of their respective supplement per kilogram of body mass thirty minutes prior to exercise protocol began and 0.17 grams of their respective supplementation every six minutes during the exercise protocol. Subjects had to complete a ten hour fasting stage and not participate in any strenuous leg exercise for seven days. The subjects performed repeated static contractions at a target 50% of maximal voluntary contractions. They performed a continuous 20 second contraction without electromyostimulation followed by 40 seconds rest period. During the last 3 seconds of the first 20 second voluntary contraction was superimposed by electromyostimulation and every five minutes thereafter. This process was carried out to quantify force output. This exercise protocol continued until subject reached exhaustion. Summary of Results/Conclusion
The results found in this study show a significant (p ≤ 0.05) increase for force output when comparing the CHO group and the PL group. Analysis of performance variables revealed that CHO group had a significantly higher time to exhaustion when compared to the PL group. Repeated measure analysis of variance did not show any significant interaction effect of blood lactate, therefore no more test were conducted for blood lactate. This study did a good job reporting results strictly based on the analysis of the two by three factorial analyses of variance as well as the paired t-tests.
Critique of the Study
The authors of this study did an excellent job with the analytic procedures for a paired t-test and two by three ANOVA. I would have recommended a Tukey’s Honestly Significant Difference test to be used because the comparisons were pairwise. Three Tukey’s tests may have had to be run in order to run one for the pre and post-test of each group. However, since F was found to be non-significant for blood lactate this would not be needed. Another concern that I had about this study pertains the sample. My main concerns about the sample were that it only consisted of six participants and that all the participants were male.
Practical Application
These findings in this study show a significant (p ≤ 0.05) increase for force output when comparing the CHO group and the PL group. Analysis of performance variables revealed that CHO group had a significantly higher time to exhaustion when compared to the PL group. Thus, based on these findings it can be beneficial to ingest CHO prior to performance in order to increase force output and time to exhaustion for athletes of all sports.
Questions
1. To what degree of training were the subjects trained? Were they all on the same level of training?
2. Does the significance of force output increase for upper body with the increase supplementation of CHO as it does for single leg static contractions?
- Thread:
- Hydration status in adolescent judo athletes before and after training in the heat
- Post:
- Hydration status in adolescent judo athletes before and after training in the heat
- Author:
- Vickie Machen
- Posted Date:
- October 5, 2012 4:54 PM
- Status:
- Published
Research Review #2
Rivera-Brown, A. M., & De Felix-Davila, R. A. (2012). Hydration status in adolescent judo athletes before and after training in the heat. International Journal of Sports Physiology & Performance, 7(1), 39-46
Purpose of Study
The art of Judo is a very demanding sport that has athletes produce high level of aerobic fitness, strength, agility, muscular endurance, and mental alertness for performance to be successful. Being that there are weight categories, many athletes resort to rapid weight loss days and hours before competition. The preferred methods for many to “make weight” include combinations of increased sweating and fluid restriction. It is well researched that dehydration hinders exercise performance and the purpose of this study was to determine the body hydration status of adolescent athletes before, immediately after, and 24 hours after a training session. Sodium loss and symptoms of hydration were documented.
Methods and Materials
Twenty-four adolescent athletes (male=14, female=10) between the ages of 12 and 17, whom were naturally accustomed to hot and humid environments, were participants for this study. All subjects and parents were informed of the purpose and procedures of the study and each handed a consent form. During the pre training session, each subject was instructed to urinate in a pre weighed container and body weight was then measured. Upon putting on their kimono, a forehead absorbent patch was used for regional sweat collection. Once prepared, the training session lasted 90minutes that included warm up, training, and cool-down. Location was set in a gymnasium that provided only fans for cooling.
Summary of Results/Conclusion
Upon receiving data it was resulted that there were no significant differences between both genders in any of the variables studied. According to the NATA guidelines, 21 of 24 subjects starting training in a “significant level” of dehydration (Rivera-Brown & De Felix Davila, 2012). Three of the subjects had started their training in a state of “serious” dehydration. There was never a complete rehydration among the athletes during training and the following day majority of the athletes regained body weight but 20 of the 21 that were in fluid deficit before training were still hypo hydrated. In relation to symptoms, 70% reported to experiencing symptoms of dehydration during training.
Critique of the Study
Strengths quickly noted in the article were the consent forms and pre discussion performed by the testers to the parents and athletes of the study. The environment was taken into account and noted within the article stating that temperature and changes were recorded every 30 minutes. It is to be noted also that all the participants were accustomed to hot and humid environments which makes the study effective. Weakness found within the article was that studies were done with adolescents. Could the results have been different if performed by older subjects? Comparison of results to more elite athletes may not be efficient so it would be wise to perform more tests but with older subjects to make comparisons.
Practical Application(s) of the Study
Overall importance to get out of this article is that rehydration is very important and crucial for optimal performance. Athletes and parents alike need to be educated about developing ways that will aid optimal hydration to get a better quality of training. Above all, dehydration should not become a factor for it can affect the well-being of athletes especially those of adolescents.
Questions:
What would the results have been if subjects were adults?
How would the comparison of accustomed athletes to unaccustomed athletes to heat and humidity be?
What results would be found if data was picked up 48 to 72 hours?
- Thread:
- The Effect of 6 Days of Sodium Phosphate Supplementation on Appetite, Energy Intake, and Aerobic Capacity in Trained Men and Women
- Post:
- The Effect of 6 Days of Sodium Phosphate Supplementation on Appetite, Energy Intake, and Aerobic Capacity in Trained Men and Women
- Author:
- Woncheol Noh
- Posted Date:
- October 9, 2013 11:37 AM
- Status:
- Published
My research review is attached.
Thank you.
Attachment: Research review 2.doc (31.5 KB)
Research review 2.doc (31.5 KB)- Thread:
- Protein Drink Improves Time to Exhaustion After Recovery from Endruance Exercise
- Post:
- Protein Drink Improves Time to Exhaustion After Recovery from Endruance Exercise
- Author:
- Christopher Williams
- Posted Date:
- October 9, 2013 10:49 AM
- Status:
- Published
Chris Williams
Research Review 2
KINE 5306 – (Advanced Nutrition)
Protein Drink Improves Time to Exhaustion After Recovery from Endruance Exercise
Reference
Niles, E. S., Lachowetz, T., John Garfi, W. S., Smith, J. C., & Brain P. Leyh, a. S. (2001). Carbohydrate-Protein Drink Improves Time to Exhaustion After Recovery from Endruance Exercise. Journal of Exercise Physiology Online, 4(1), 45-52.
Purpose of Study
The purpose of this study was to examine and compare the effects of isocaloric carbohydrate (CHO, 152.7 g) drinks verses carbohydrate-protein (CHO- PRO, 112 g CHO with 40.7 g PRO) drinks ingested after a glycogen lowering diet and exercise bout. It was hypothesized that the addition of protein after exercise for trained endurance male athletes would lead to quicker glycogen synthesis and repletion.
Methods and Materials
The design of the study was a repeated measures, double-blind and counter-balanced study. Subjects were randomly assigned to the different treatments of CHO drinks or CHO-PRO drinks. The subjects consisted of ten male trained runners ages 24-34 years and had a minimum VO2 peak of 50 mL/kg/min and a body fat percentage of 15%. All subjects fasted over night for a period of 12 hours before being tested and test were administered in the same laboratory with a consistent temperature. Skinfold and multiple body measurements were taken before the initial glycogen depletion run of 45 minutes was administered on a treadmill. The exercise intensity for the treadmill was set at 80% of the subject’s personal VO2 peak for the first 30 minutes of the run and then was decreased to 70-75% of VO2 peak for the rest of the run. The runners V02 was taken via a mask for analysis for the first 10-12 minutes of the first trail. The mask was re-attached 30 minutes into the run to monitor the subjects drop in intensity. Once the runners VO2 leveled off the mask was removed for the remainder of the run. A blood sample was taken at the 40 minute mark to obtain levels of plasma glucose to be analyzed. After the initial run subjects were given their appropriate CHO or CHO-PRO drink. Subjects were given the same dosages 60 minutes after their first drink. During the second treatment session, the run was stopped when the subject’s plasma glucose levels were within 5 mg/100 mL of the first run. The tests and drinks were given again about week after their initial runs.
Statistical analysis was determined by using a 2 x 2 factorial repeated measures ANOVA tests. A paired test was used to determine if there were any mean differences between run time to exhaustion trails.
SSPS for the Social Sciences was used to analyze all data.
Summary of Results and Conclusion
With respect to insulin levels, the study found that 90 minutes into the exhaustion run, insulin levels were higher in the CHO-PRO trail than the CHO only trail. There was no significant difference found with the levels of glucose between the two trails. The most significant finding was that run time to exhaustion for the CHO-PRO trail was longer with an increase of 21.2% time to exhaustion. The study concluded that the muscle glycogen repairing process was quickened when subjects ingested a drink containing both CHO and PRO compared to a CHO only drink.
Critique of the Study
A key factor in the success of the study was the baseline tests administered to all subjects and the consistent use of a treadmill as an ergometer. The masked used to measure VO2max along with the levels of intensity set on the treadmill made it easy to accurately measure the runner’s effort during each trail. The fact that the subjects had to complete a second exhaustion run after the repletion drink was a bit of a surprise and a change from other studies who merely measure the subjects after only one run. The study may be improved by testing female subjects or untrained individuals.
Practical Application of the Study
The study did demonstrate a strong case for using a CHO-PRO drink as a means of replenishing runners who partake in endurance type events. The study is applicable for many athletes who may engage in multiple practice, training, or competitions in one day.
Questions
I’m interested in how the study would have turned out if it was done on untrained individuals?
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