What Determines the Magnitude of the Q Angle? A Preliminary Study of Selected Skeletal and Muscular Measures

2000 ◽  
Vol 9 (1) ◽  
pp. 26-34 ◽  
Author(s):  
Timo Byl ◽  
Jennifer A. Cole ◽  
Lori A. Livingston
Keyword(s):  
Outcome Measures ◽  
Peak Torque ◽  
Knee Extension ◽  
Quadriceps Strength ◽  
Femur Length ◽  
Q Angle ◽  
Preliminary Study ◽  
The Right ◽  
Knee Extension Exercise

Context:Q-angle size has been found to correlate poorly with skeletal measures of pelvic breadth and femur length. Because the patella is exposed to the forces of quadriceps contraction, muscular forces might also affect Q-angle magnitude.Objective:To compare bilateral measurements of the Q angle with selected skeletal and muscular strength measures.Design:In vivo study of anthropometric and quadriceps peak torque measures.Setting:Research laboratory.Participants:Thirty-four healthy men and women, mean age 20.9 ± 2.7 years.Main Outcome Measures:Q angles, pelvic breadths, femur lengths, and peak torque during dynamic knee-extension exercise, normalized to body weight.Results:Significant differences in Q-angle magnitude, femur length, and peak torqueBW were observed between sexes, but not between limbs. Pelvic breadth did not differ significantly between sexes. Correlational analysis revealed a weak, yet significant, linear relationship between Q angle and peak torqueBW in the right lower limb.Conclusions:These findings lend some support to the notion that Q-angle magnitude is inversely related to quadriceps strength.

Can Hip Joint Position affect Quadriceps Muscle Responses during Knee Extension Exercise?

2020 ◽  
Vol 41 (13) ◽  
pp. 929-935
Author(s):  
Denis César Leite Vieira ◽  
Marco Aurélio Araujo Dourado ◽  
Lucas Ugliara ◽  
Joao Luiz Quagliotti Durigan ◽  
Brad J. Schoenfeld ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Muscle Thickness ◽  
Rectus Femoris ◽  
Peak Torque ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Knee Extensors ◽  
Work Output ◽  
Before And After ◽  
Knee Extension Exercise

AbstractThis study investigated the acute effects of seated and supine knee extension exercise on muscle swelling, torque, and work output. Twelve resistance-trained men performed two isokinetic concentric-only knee-extension training protocols at different hip positions in a counter-balanced order. They completed the knee extension exercise in the seated (hip angle at 85°) and supine (hip angle at 180°) positions. The torque and work output were assessed during each set. Moreover, muscle thickness of the middle and proximal vastus lateralis and rectus femoris were evaluated before and after each protocol and used as an indicator of muscle swelling. Middle rectus femoris and proximal vastus lateralis thickness increased significantly (p=0.01) with no difference between exercise variations. However, the middle vastus lateralis thickness increased (p=0.01) only after the seated knee extension exercise (~7%). Knee extensors’ peak torque and work output were approximately 8% higher (p=0.04) in the seated when compared to the supine hip position. There was a similar decrease in torque and work output throughout both protocols (p=0.98). In conclusion, seated knee extension exercises produced greater torque, work output, and muscle swelling in the vastus lateralis when compared to the supine knee extension exercise.

Q-Angle: A Factor in Peak Torque Occurrence in Isokinetic Knee Extension

1988 ◽  
Vol 9 (7) ◽  
pp. 250-2253 ◽  
Author(s):  
Leanne K. Lyon ◽  
Laurence N. Benz ◽  
Kevin K. Johnson ◽  
Agnes C. Ling ◽  
Jean M. Bryan
Keyword(s):  
Peak Torque ◽  
Knee Extension ◽  
Q Angle

Mitochondrial respiration in creatine-loaded muscle: is there 31P-MRS evidence of direct effects of phosphocreatine and creatine in vivo?

2006 ◽  
Vol 100 (4) ◽  
pp. 1428-1430 ◽  
Author(s):  
Graham Kemp
Keyword(s):  
Respiration Rate ◽  
Mitochondrial Respiration ◽  
Strong Relationship ◽  
Knee Extension ◽  
Resonance Spectroscopy ◽  
Direct Effects ◽  
The Relationship ◽  
Knee Extension Exercise ◽  
Moderate Relationship

Recent human isolated muscle fiber studies suggest that phosphocreatine (PCr) and creatine (Cr) concentrations play a role in the regulation of mitochondrial respiration rate. To determine whether similar regulatory mechanisms are present in vivo, this study examined the relationship between skeletal muscle mitochondrial respiration rate and end-exercise PCr, Cr, PCr-to-Cr ratio (PCr/Cr), ADP, and pH by using 31P-magnetic resonance spectroscopy in 16 men and women (36.9 ± 4.6 yr). The initial PCr resynthesis rate and time constant (Tc) were used as indicators of mitochondrial respiration after brief (10–12 s) and exhaustive (1–4 min) dynamic knee extension exercise performed in placebo and creatine-supplemented conditions. The results show that the initial PCr resynthesis rate has a strong relationship with end-exercise PCr, Cr, and PCr/Cr ( r > 0.80, P < 0.001), a moderate relationship with end-exercise ADP ( r = 0.77, P < 0.001), and no relationship with end-exercise pH ( r = −0.14, P = 0.34). The PCr Tc was not as strongly related to PCr, Cr, PCr/Cr, and ADP ( r < 0.77, P < 0.001–0.18) and was significantly influenced by end-exercise pH ( r = −0.43, P < 0.01). These findings suggest that end-exercise PCr and Cr should be taken into consideration when PCr recovery kinetics is used as an indicator of mitochondrial respiration and that the initial PCr resynthesis rate is a more reliable indicator of mitochondrial respiration compared with the PCr Tc.

Use of phosphocreatine kinetics to determine the influence of creatine on muscle mitochondrial respiration: an in vivo 31P-MRS study of oral creatine ingestion

2004 ◽  
Vol 96 (6) ◽  
pp. 2288-2292 ◽  
Author(s):  
Sinclair A. Smith ◽  
Scott J. Montain ◽  
Gary P. Zientara ◽  
Roger A. Fielding
Keyword(s):  
Respiration Rate ◽  
Mitochondrial Respiration ◽  
Strong Relationship ◽  
Knee Extension ◽  
Regulatory Mechanisms ◽  
Resonance Spectroscopy ◽  
The Relationship ◽  
Knee Extension Exercise ◽  
Moderate Relationship

Recent human isolated muscle fiber studies suggest that phosphocreatine (PCr) and creatine (Cr) concentrations play a role in the regulation of mitochondrial respiration rate. To determine whether similar regulatory mechanisms are present in vivo, this study examined the relationship between skeletal muscle mitochondrial respiration rate and end-exercise PCr, Cr, PCr-to-Cr ratio (PCr/Cr), ADP, and pH by using 31P-magnetic resonance spectroscopy in 16 men and women (36.9 ± 4.6 yr). The initial PCr resynthesis rate and time constant (Tc) were used as indicators of mitochondrial respiration after brief (10–12 s) and exhaustive (1–4 min) dynamic knee extension exercise performed in placebo and creatine-supplemented conditions. The results show that the initial PCr resynthesis rate has a strong relationship with end-exercise PCr, Cr, and PCr/Cr ( r > 0.80, P < 0.001), a moderate relationship with end-exercise ADP ( r = 0.77, P < 0.001), and no relationship with end-exercise pH ( r = -0.14, P = 0.34). The PCr Tc was not as strongly related to PCr, Cr, PCr/Cr, and ADP ( r < 0.77, P < 0.001–0.18) and was significantly influenced by end-exercise pH ( r = -0.43, P < 0.01). These findings suggest that end-exercise PCr and Cr should be taken into consideration when PCr recovery kinetics is used as an indicator of mitochondrial respiration and that the initial PCr resynthesis rate is a more reliable indicator of mitochondrial respiration compared with the PCr Tc.

scholarly journals In Vivo Ciprofloxacin Release from Hydroxyapatite-Based Bone Implants in Rabbit Tibia: A Preliminary Study

2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
Amit Kumar Nayak ◽  
Ajoy Bhattacharyya ◽  
Kalyan Kumar Sen
Keyword(s):  
Guar Gum ◽  
Preliminary Investigation ◽  
Hplc Method ◽  
Preliminary Evaluation ◽  
Bone Implants ◽  
Rabbit Tibia ◽  
Preliminary Study ◽  
The Right ◽  
Local Antibiotic

The present study deals with the preliminary evaluation of in vivo ciprofloxacin release from HAp-ciprofloxacin bone implants in rabbit tibia. The HAp-ciprofloxacin implants ( mm) were prepared using various HAp-ciprofloxacin composites synthesized by precipitation technique and 1.5% w/v guar gum as a binder. 5 implants were implanted in artificial cortical bone window at the right proximal tibia of each rabbit. After 3- and 6-day intervals, the rabbits were euthanized. Bone marrow and serum concentrations of ciprofloxacin were determined from the harvested tibia using HPLC method. The results displayed the availability of elevated local antibiotic concentration at the implanted site with the limitation of systemic antibiotic exposure, which can be useful to minimize the risk of systemic toxicity-related side effects. This study is the preliminary investigation of the suitability of in vivo ciprofloxacin release from HAp-ciprofloxacin bone implants in rabbit tibia, after implantation, and these implants can be useful for the treatment of bacterial bone infections like osteomyelitis.

Knee-Extension Exercise’s Lack of Immediate Effect on Maximal Voluntary Quadriceps Torque and Activation in Individuals With Anterior Knee Pain

2012 ◽  
Vol 21 (2) ◽  
pp. 119-126 ◽  
Author(s):  
Jihong Park ◽  
Terry L. Grindstaff ◽  
Joe M. Hart ◽  
Jay N. Hertel ◽  
Christopher D. Ingersoll
Keyword(s):  
Outcome Measures ◽  
Knee Pain ◽  
Anterior Knee Pain ◽  
Controlled Trial ◽  
Weight Bearing ◽  
Knee Extension ◽  
Maximal Voluntary Isometric Contraction ◽  
Acute Changes ◽  
Knee Extension Exercise ◽  
Anterior Knee

Context:Weight-bearing (WB) and non-weight-bearing (NWB) exercises are commonly used in rehabilitation programs for patients with anterior knee pain (AKP).Objective:To determine the immediate effects of isolated WB or NWB knee-extension exercises on quadriceps torque output and activation in individuals with AKP.Design:A single-blind randomized controlled trial.Setting:Laboratory.Participants:30 subjects with self-reported AKP.Interventions:Subjects performed a maximal voluntary isometric contraction (MVIC) of the quadriceps (knee at 90°). Maximal voluntary quadriceps activation was quantified using the central activation ratio (CAR): CAR = MVIC/(MVIC + superimposed burst torque). After baseline testing, subjects were randomized to 1 of 3 intervention groups: WB knee extension, NWB knee extension, or control. WB knee-extension exercise was performed as a sling-based exercise, and NWB knee-extension exercise was performed on the Biodex dynamometer. Exercises were performed in 3 sets of 5 repetitions at approximately 55% MVIC. Measurements were obtained at 4 times: baseline and immediately and 15 and 30 min postexercise.Main Outcome Measures:Quadriceps torque output (MVIC: N·m/Kg) and quadriceps activation (CAR).Results:No significant differences in the maximal voluntary quadriceps torque output (F2,27 = 0.592, P = .56) or activation (F2,27 = 0.069, P = .93) were observed among the 3 treatment groups.Conclusions:WB and NWB knee-extension exercises did not acutely change quadriceps torque output or activation. It may be necessary to perform exercises over a number of sessions and incorporate other disinhibitory interventions (eg, cryotherapy) to observe acute changes in quadriceps torque and activation.

Heterogeneity of human adaptations to bed rest and hypoxia: a retrospective analysis within the skeletal muscle oxidative function

2021 ◽  
Author(s):  
Desy Salvadego ◽  
Bruno Grassi ◽  
Michail E. Keramidas ◽  
Ola Eiken ◽  
Adam C. McDonnell ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Mitochondrial Respiration ◽  
Bed Rest ◽  
Knee Extension ◽  
Large Variability ◽  
The Individual ◽  
Oxidative Function ◽  
Knee Extension Exercise ◽  
Permeabilized Muscle

This retrospective study was designed to analyse the interindividual variability in the responses of different variables characterizing the skeletal muscle oxidative function to normoxic (N-BR) and hypoxic (H-BR) bed rests, and to a hypoxic ambulatory confinement (H-AMB) of 10 and 21 days. We also assessed whether and how the addition of hypoxia to bed rest might influence the heterogeneity of the responses. In vivo measurements of O2 uptake and muscle fractional O2 extraction were carried out during an incremental one-leg knee-extension exercise. Mitochondrial respiration was assessed in permeabilized muscle fibers. A total of 17 subjects were included in this analysis. This analysis revealed a similar variability among subjects in the alterations induced by N-BR and H-BR both in peak O2 uptake (SD: 4.1 and 3.3% after 10 days; 4.5 and 8.1% after 21 days, respectively) and peak muscle fractional O2 extraction (SD: 5.9 and 7.3% after 10 days; 6.5 and 7.3% after 21 days), independently from the duration of the exposure. The individual changes measured in these variables were significantly related (r=0.66, P=0.004 after N-BR; r=0.61, P=0.009 after H-BR). Mitochondrial respiration showed a large variability of response after both N-BR (SD: 25.0 and 15.7% after 10 and 21 days) and H-BR (SD: 13.0 and 19.8% after 10 and 21 days), no correlation was found between N-BR and H-BR changes. When added to bed rest, hypoxia altered the individual adaptations within the mitochondria but not those intrinsic to the muscle oxidative function in vivo, both after short and medium-term exposures.

Effect of verbal encouragement on quadriceps and knee joint function during three sets of knee extension exercise

2020 ◽  
pp. 1-7
Author(s):  
Hyunwook Lee ◽  
Jaeyoon Shin ◽  
Daeho Kim ◽  
Jihong Park
Keyword(s):  
Knee Joint ◽  
Knee Flexion ◽  
Knee Extension ◽  
Quadriceps Strength ◽  
Contributing Factors ◽  
Force Output ◽  
Joint Function ◽  
Central Activation ◽  
Verbal Encouragement ◽  
Knee Extension Exercise

BACKGROUND: Although the common practice of verbal encouragement is scientifically supported, its effect on the maintenance of force output in fatiguing exertions is unknown. OBJECTIVE: To examine the effects of verbal encouragement on exercise-induced quadriceps and knee joint function during three sets of knee extension exercise. METHODS: Sixty-five healthy males (23.3 years, 175.8 cm, 75.3 kg) underwent testing using the administration of verbal encouragement (n= 32) or not (n= 33) during assessment of quadriceps and knee joint function. Assessments were performed at baseline and times 1, 2, and 3. The knee concentric isokinetic extension at 60∘/s, was performed between the time points. For quadriceps function, maximal isometric strength and activation (central activation ratio) were recorded. Absolute error values on knee flexion replications at 15∘ or 45∘ were recorded for knee joint function. RESULTS: There was no verbal encouragement effect over three sets of exercise in quadriceps strength (condition × time: F3,189= 1.71, p= 0.17) and knee flexion replication (condition × time for 15∘: F3,189= 0.11, p= 0.96; 45∘: F3,189= 0.63, p= 0.6). However, subjects who had received verbal encouragement maintained quadriceps activation (condition × time: F3,189= 5.49, p= 0.001). Specifically, quadriceps activation in the verbal condition was 3.0% higher at time 2 (p= 0.01) and 4.7% higher at time 3 (p= 0.0003) versus in the non-verbal condition. CONCLUSIONS: Verbal encouragement appears to be effective in maintaining central activation, but is insufficient for promoting strength. This supports the idea that peripheral contributing factors play a larger role in force production when performing multiple sets of exercises.

Using Motor Imagery Training to Increase Quadriceps Strength: A Pilot Study

2018 ◽  
Vol 80 (1-2) ◽  
pp. 87-92 ◽  
Author(s):  
Tyler M. Saumur ◽  
Stephen D. Perry
Keyword(s):  
Strength Training ◽  
Motor Imagery ◽  
Training Group ◽  
Peak Torque ◽  
Knee Extension ◽  
Quadriceps Strength ◽  
Imagery Training ◽  
Brief Training ◽  
And Control ◽  
The Impact

Background: Motor imagery training implements neural adaptation theory to improve muscle strength without physically performing muscle contractions. To date, motor imagery training research regarding the efficacy of improving torque of the quadriceps over a brief training period is limited. Objective: To determine the impact of a 3-week motor imagery training on peak torque during knee extension. Method: Ten young, healthy volunteers were randomly assigned to 1 of 3 groups over a 3-week period: strength training, motor imagery training and control. Results: Following training, an increase in peak torque was observed in all strength training participants (mean change of 38 ± 15%) and in 2 members of the motor imagery training group (45 ± 10%). Conclusion: Brief periods of motor imagery training may have the potential to improve quadriceps strength; however, more research is needed with larger populations to test this hypothesis.

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