The Effect of Muscle Fatigue on Muscle Force-Couple Activation of the Shoulder

2001 ◽  
Vol 10 (4) ◽  
pp. 246-256 ◽  
Author(s):  
Timothy J. Henry ◽  
Scott M. Lephart ◽  
Jorge Giraldo ◽  
David Stone ◽  
Freddie H. Fu
Keyword(s):  
Muscle Fatigue ◽  
Outcome Measures ◽  
Muscle Force ◽  
Glenohumeral Joint ◽  
Previous History ◽  
Type Design ◽  
Before And After ◽  
History Of ◽  
Male Subjects ◽  
Force Couple

Context:Muscle fatigue is an important concept in regard to the muscle function of the shoulder joint. Its effect on the muscle force couples of the glenohumeral joint has not been fully identified.Objective:To examine the effects of muscle fatigue on muscle force-couple activation in the normal shoulder.Design:Pretest, posttest.Patients:Ten male subjects, age 18–30 years, with no previous history of shoulder problems.Main Outcome Measures:EMG (area) values were assessed for the anterior and middle deltoid, subscapularis, and infraspinatus muscles during 4 dynamic stabilizing exercises before and after muscle fatigue. The exercises examined were a push-up, horizontal abduction, segmental stabilization, and rotational movement on a slide board.Results:No significant differences were observed for any of the muscles tested.Conclusions:The results of our study indicate that force-couple coactivation of the glenohumeral joint is not significantly altered after muscle fatigue.

Effect of Posterior Capsule Tightness on Glenohumeral Translation in the Late-Cocking Phase of Pitching

2007 ◽  
Vol 16 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Kim M. Clabbers ◽  
John D. Kelly ◽  
Dov Bader ◽  
Matthew Eager ◽  
Carl Imhauser ◽  
...  
Keyword(s):  
Outcome Measures ◽  
Humeral Head ◽  
Glenohumeral Joint ◽  
External Rotation ◽  
Head Position ◽  
Posterior Capsule ◽  
Nonsignificant Trend ◽  
Before And After ◽  
Fresh Frozen ◽  
Head Translation

Context:Throwing injuries.Objective:To study the effects of posterior capsule tightness on humeral head position in late cocking simulation.Design:Eight fresh frozen shoulders were placed in position of “late cocking,” 90 degrees abduction, and 10 degrees adduction and maximal external rotation. 3D measurements of humeral head relationship to the glenoid were taken with an infrared motion sensor, both before and after suture plication of the posterior capsule. Plications of 20% posterior/inferior capsule and 20% entire posterior capsule were performed, followed by plications of 40% of the posterior/inferior capsule and 40% entire posterior capsule.Setting:Cadaver Lab.Intervention:Posterior capsular placation.Main Outcome Measures:Humeral head position.Results:40%, but not 20%, posterior/inferior and posterior plications demonstrated a trend to increased posterior-superior humeral head translation relative to controls.Conclusion:Surgically created posterior capsular tightness of the glenohumeral joint demonstrated a nonsignificant trend to increased posterior/superior humeral head translation in the late cocking position of throwing.

Difference in Ratio of Evertor to Invertor Activity Between the Dominant and Nondominant Legs During Simulated Lateral Ankle Sprain

2013 ◽  
Vol 22 (4) ◽  
pp. 272-278 ◽  
Author(s):  
Adam C. Knight ◽  
Wendi H. Weimar
Keyword(s):  
Outcome Measures ◽  
Ankle Sprain ◽  
Muscle Activity ◽  
Repeated Measures ◽  
Previous History ◽  
Physically Active ◽  
Lateral Ankle ◽  
History Of ◽  
University Laboratory

Context:The dominant and nondominant legs respond asymmetrically during landing tasks, and this difference may occur during an inversion perturbation and provide insight into the role of ankle-evertor and -invertor muscle activity.Objective:To determine if there is a difference in the ratio of evertor to invertor activity between the dominant and nondominant legs and outer-sole conditions when the ankle is forced into inversion.Design:Repeated-measures single-group design.Setting:University laboratory.Participants:15 physically active healthy volunteers with no previous history of an ankle sprain or lower extremity surgery or fracture.Interventions:An outer sole with fulcrum was used to cause 25° of inversion at the subtalar joint after landing from a 27-cm step-down task. Participants performed 10 fulcrum trials on both the dominant and nondominant leg.Main Outcome Measures:The ratio of evertor to invertor muscle activity 200 ms before and 200 ms after the inversion perturbation was measured using electromyography. This ratio was the dependent variable. Independent variables included outer-sole condition (fulcrum, flat), leg (dominant, nondominant), and time (prelanding, postlanding). The data were analyzed with separate 2-way repeated-measures ANOVA, 1 for the prelanding ratios and 1 for the postlanding ratios.Results:For the postlanding ratios, the fulcrum outer sole had a significantly greater (P < .05) ratio than the flat outer sole, and the nondominant leg had a significantly greater (P < .05) ratio than the dominant leg.Conclusions:These results indicate that a greater evertor response is produced when the ankle is forced into inversion, and a greater response is produced for the nondominant leg, which may function better during a postural-stabilizing task than the dominant leg.

The effects of priming exercise on the V̇O2 slow component and the time-course of muscle fatigue during very-heavy-intensity exercise in humans

2018 ◽  
Vol 43 (9) ◽  
pp. 909-919 ◽  
Author(s):  
Paulo Cesar do Nascimento Salvador ◽  
Kristopher Mendes de Souza ◽  
Ricardo Dantas De Lucas ◽  
Luiz Guilherme Antonacci Guglielmo ◽  
Benedito Sérgio Denadai
Keyword(s):  
Muscle Fatigue ◽  
Time Course ◽  
Slow Component ◽  
Peak Torque ◽  
Fixed Amount ◽  
Prior Exercise ◽  
Before And After ◽  
Priming Exercise ◽  
Male Subjects ◽  
Exercise In Humans

We hypothesized that prior exercise would attenuate the muscle fatigue accompanied by oxygen uptake slow-component (V̇O2SC) behavior during a subsequent very-heavy (VH)-intensity cycling exercise. Thirteen healthy male subjects performed tests to determine the critical power (CP) and the fixed amount of work above CP ([Formula: see text]) and performed 6 square-wave bouts until 3 or 8 min, each at a work rate set to deplete 70% [Formula: see text] in 8 min, with a maximal isokinetic effort before and after the conditions without (VHCON) and with prior exercise (VHEXP), to measure the cycling peak torque decrement. The V̇O2SC magnitude at 3 min (VHCON = 0.280 ± 0.234, VHEXP = 0.116 ± 0.109 L·min−1; p = 0.04) and the V̇O2SC trajectory were significantly lower for VHEXP (VHCON = 0.108 ± 0.042, VHEXP = 0.063 ± 0.031 L·min−2; p < 0.01), leading to a V̇O2SC magnitude at the eighth minute that was significantly lower than VHCON (VHCON = 0.626 ± 0.296 L·min−1, VHEXP = 0.337 ± 0.179; p < 0.01). Conversely, peak torque progressively decreased from pre-exercise to 3 min (Δtorque = 21.5 ± 7.7 vs. 19.6 ± 9.2 Nm) and to 8 min (Δtorque = 29.4 ± 15.8 vs. 27.5 ± 12.0 Nm) at VHCON and VHEXP, respectively, without significant differences between conditions. Regardless of the condition, there was a significant relationship between Δtorque and the V̇O2SC (R2: VHCON = 0.23, VHEXP = 0.25; p = 0.01). Considering that “priming” effects on the V̇O2SC were not accompanied by the muscle force behavior, these findings do not support the hypothesis of a “causal” relationship between the time-course of muscle fatigue and V̇O2SC.

Augmented Feedback Reduces Ground Reaction Forces in the Landing Phase of the Volleyball Spike Jump

2008 ◽  
Vol 17 (2) ◽  
pp. 148-159 ◽  
Author(s):  
John B. Cronin ◽  
Eadric Bressel ◽  
Loren Finn
Keyword(s):  
Body Weight ◽  
Outcome Measures ◽  
Collegiate Athletes ◽  
Ground Reaction Forces ◽  
Single Session ◽  
Augmented Feedback ◽  
Type Design ◽  
Division 1 ◽  
Before And After ◽  
Reaction Forces

Context:Frequency and magnitude of ground reaction forces (GRF) have been implicated in causing injuries such as “jumpers knee.”Objective:To investigate whether a single session of augmented feedback concerning landing technique would decrease GRF.Design:Pretest posttest experimental design.Setting:University biomechanics laboratory.Participants:Fifteen female Division 1 intercollegiate volleyball players.Intervention:Participants were required to land on a force platform after spiking a volleyball from a four-step approach before and after an intervention involving visual and aural augmented feedback on correct jumping and landing technique.Main Outcome Measures:Mediolateral (ML), anterioposterior (AP), and vertical (V) GRF normalized to body weight (BW).Results:Augmented feedback was found to significantly (P = 0.01) decrease VGRF by 23.6% but not ML (25%, P = 0.16) and AP (4.9%, P = 0.40) peak GRF.Conclusions:A single session of augmented feedback may be effective in reducing VGRF in collegiate athletes.

The Effect of Functional Training on the Incidence of Shoulder Pain and Strength in Intercollegiate Swimmers

2002 ◽  
Vol 11 (2) ◽  
pp. 140-154 ◽  
Author(s):  
Kathleen A. Swanik ◽  
C. Buz Swanik ◽  
Scott M. Lephart ◽  
Kellie Huxel
Keyword(s):  
Shoulder Pain ◽  
Outcome Measures ◽  
Repeated Measures ◽  
Functional Training ◽  
Type Design ◽  
Significant Strength ◽  
Before And After ◽  
Shoulder Strength ◽  
Weight Room ◽  
And Control

Objective:To determine whether functional training reduces the incidence of shoulder pain and increases strength in intercollegiate swimmers.Design:Pretest–posttest.Setting:Laboratory and weight room.Participants:26 intercollegiate swimmers (13 men, 13 women).Intervention:6-wk functional training program.Main Outcome Measures:Incidence of shoulder pain was recorded throughout the study. Isokinetic shoulder strength was assessed before and after training.Results:Attest showed significant differences (P< .05) for the incidence of shoulder pain between the experimental (mean episodes = 1.8 ± 2.1) and control (mean episodes = 4.6 ± 4.7) groups. ANOVA with repeated measures revealed no significant strength differences between groups but exhibited significant within-group increases.Conclusions:Incorporating functional exercises might reduce incidence of shoulder pain in swimmers. The results also validate the need to modify preventive programs as the demands of the sport change throughout the season.

How Back-Muscle Fatigue Influences Lumbar Curvature

2009 ◽  
Vol 18 (2) ◽  
pp. 327-336 ◽  
Author(s):  
Yukio Takihara ◽  
Yukio Urabe ◽  
Gaston Ariel Nishiwaki ◽  
Kosuke Tanaka ◽  
Koji Miyashita
Keyword(s):  
Low Back Pain ◽  
Back Pain ◽  
Lumbar Spine ◽  
Muscle Fatigue ◽  
Outcome Measures ◽  
Lower Portion ◽  
Low Back ◽  
Back Muscle ◽  
Healthy Men ◽  
Type Design

Context:Back-muscle fatigue and lumbar curvature are related to low back pain, but the relation between them is unknown.Objective:To clarify whether lumbar curvature changes with back-muscle fatigue.Design:Prospective pseudorandomized.Setting:Laboratory.Participants:13 healthy men without low back pain.Intervention:To induce back-muscle fatigue, subjects performed a repetitive prone back-extension exercise from 45° to 0° until exhaustion and then rested 10 min. They performed this exercise 3 times.Main Outcome Measures:Before the trial and after each exercise, lumbar curvature was measured with a Spinal Mouse.Results:After back-muscle fatigue, lumbar curvature decreased significantly (P < .01). This decrease occurred at L4–S1, which was defined as the lower spine. On the contrary, curvature of the upper lumbar spine, at Th12–L4, did not decrease.Conclusion:Lumbar curvature, especially the lower portion, decreased with back-muscle fatigue induced by prone back-extension exercise.

Subconcussive Head Impacts and Neurocognitive Function Over 3 Seasons of Youth Football

2021 ◽  
pp. 088307382110044
Author(s):  
Sean C. Rose ◽  
Keith Owen Yeates ◽  
Joseph T. Nguyen ◽  
Patrick M. Ercole ◽  
Natalie M. Pizzimenti ◽  
...  
Keyword(s):  
Outcome Measures ◽  
Social Adjustment ◽  
Neuropsychological Testing ◽  
Football Players ◽  
Cumulative Impact ◽  
Head Impacts ◽  
Before And After ◽  
History Of ◽  
Tackle Football ◽  
Neurobehavioral Outcomes

Objective: To determine the association between repetitive subconcussive head impacts and neurobehavioral outcomes in youth tackle football players. Methods: Using helmet-based sensors, we measured head impacts for 3 consecutive seasons of play in 29 male players age 9-11. Cumulative impact g’s were calculated. Players completed a battery of outcome measures before and after each season, including neuropsychological testing, vestibular-ocular sensitivity, and self- and parent-reported measures of symptoms and attention-deficit hyperactivity disorder (ADHD). Results: Average cumulative impact over 3 seasons was 13 900 g. High-intensity hits predicted worse change for self-reported social adjustment ( P = .001). Cumulative impact did not predict change in any of the outcome measures. History of ADHD, anxiety, and depression predicted worse change for self-reported symptoms and social adjustment, independent of head impacts. When players were stratified into 3 groups based on cumulative impact across all 3 seasons, differences in outcome measures existed prior to the start of the first season. These differences did not further increase over the course of the 3 seasons. Conclusion: Over 3 consecutive seasons of youth tackle football, we found no association between cumulative head impacts and neurobehavioral outcomes. Larger sample sizes and longer follow-up times would further assist in characterizing this relationship.

Serum Procalcitonin and Calcitonin Normal Values Before and After Calcium Gluconate Infusion

2012 ◽  
Vol 120 (03) ◽  
pp. 169-170 ◽  
Author(s):  
L. Giovanella
Keyword(s):  
Calcium Gluconate ◽  
Blood Donors ◽  
Neuroendocrine Tumours ◽  
Normal Values ◽  
Inflammatory Diseases ◽  
C Cells ◽  
Before And After ◽  
History Of ◽  
Male Subjects ◽  
Intravenous Calcium

AbstractTo evaluate and compare serum procalcitonin (PCT) and calcitonin (hCT) levels before and after stimulation with intravenous calcium gluconate in selected thyroid healthy subjects.There were enrolled 78 healthy blood donors with no history of thyroid disease, renal disease, neuroendocrine tumours, infections or inflammatory diseases, and taking no proton-pump inhibitors medication. Serum PCT and hCT were measured before and after intravenous injection of 2.5 mg/kg calcium gluconate.Undetectable basal PCT values were found in all subjects while a marginal increase occurred only in 2 male subjects after stimulation. The basal and stimulated 95th percentile hCT values were 7.80 pg/mL and 102 pg/mL in males and 5.20 pg/mL and 78.5 pg/mL in females, respectively.Our data suggest that calcium gluconate physiologically stimulate the release of mature hCT molecule from the parafollicular C-cells with no or minimal effects on the PCT release. Our preliminary results form a reliable reference platform for basal and calcium-stimulated PCT measurements in clinical studies.

PERIOPERATIVE MANAGEMENT OF MANDIBULAR FRACTURES IN A PATIENT WITH SEVERE HYPERTHYROIDISM: A CASE REPORT

2016 ◽  
Vol 19 (04) ◽  
pp. 1672003 ◽  
Author(s):  
Sayaka Mishima ◽  
Katsu Takahashi ◽  
Marika Hori ◽  
Toru Komatani ◽  
Junko Yamada ◽  
...  
Keyword(s):  
Perioperative Management ◽  
Oral Care ◽  
Previous History ◽  
Emergency Admission ◽  
Mandibular Fractures ◽  
Propranolol Hydrochloride ◽  
Laboratory Findings ◽  
Thyroid Crisis ◽  
Before And After ◽  
History Of

Purpose: In this report, we had managed to perioperative of mandibular fractures in a patient with severe hyperthyroidism. Methods: A 26-year-old man required emergency admission to the hospital after having a fall and losing consciousness. A computed tomography (CT) scan revealed a fracture line in the mental region and both sides of the condyle. He had a previous history of hyperthyroidism and was prescribed thiamazole, propranolol hydrochloride, and potassium iodide, but he did not take medicine by self-judgement. His laboratory findings were as follows: FT3, 7.53[Formula: see text]pg/mL; FT4, 4.26[Formula: see text]ng/mL; and TSH, undetectable. Therefore, we planned for surgery immediately after his condition improved. We also postponed his maxilla-mandibular fixation (MMF) procedure because there was a probability that MMF procedure caused thyroid crisis. Result: Seventeen days after his injury, he had greatly reduced his risk of having thyroid crisis, he underwent open reduction of his mandibular fractures under general anesthesia. As perioperative management, the patient underwent an opening training and oral care before and after surgery in addition to thyroidal treatment. Conclusion: The procedures prevented adhesion of temporomandibular joint and recovered aperture size. Moreover, we diagnosed agranulocytosis from intraoral lesion and obtained good course in response to early.

Gastrocnemius Stretching Program: More Effective in Increasing Ankle/Rear-Foot Dorsiflexion When Subtalar Joint Positioned in Pronation Than in Supination

2015 ◽  
Vol 24 (3) ◽  
pp. 307-314 ◽  
Author(s):  
Marie A. Johanson ◽  
Megan Armstrong ◽  
Chris Hopkins ◽  
Meghan L. Keen ◽  
Michael Robinson ◽  
...  
Keyword(s):  
Outcome Measures ◽  
Subtalar Joint ◽  
Mixed Model ◽  
Controlled Trial ◽  
Cumulative Trauma ◽  
Mixed Model Anova ◽  
Main Effect ◽  
Before And After ◽  
History Of ◽  
Analysis System

Context:Stretching exercises are commonly prescribed for patients and healthy individuals with limited extensibility of the gastrocnemius muscle.Objective:To determine if individuals demonstrate more dorsiflexion at the ankle/rear foot and less at the midfoot after a gastrocnemius-stretching program with the subtalar joint (STJ) positioned in supination compared with pronation.Design:Randomized controlled trial.Setting:Biomechanical laboratory.Participants:22 volunteers with current or recent history of lower-extremity cumulative trauma and gastrocnemius tightness (10 women and 4 men, mean age 28 y) randomly assigned to stretching groups with the STJ positioned in either pronation (n = 11) or supination (n = 11).Intervention:3-wk home gastrocnemius-stretching program using a template to place the subtalar joint in either a pronated or a supinated position.Main Outcome Measures:A 7-camera Vicon motion-analysis system measured ankle/rear-foot dorsiflexion and midfoot dorsiflexion of all participants during stretching with the STJ positioned in both pronation and supination before and after the 3-wk gastrocnemius-stretching program.Results:A 2-way mixed-model ANOVA revealed a significant interaction (P = .019). At posttest, the group who performed the 3-week stretching program with the STJ positioned in pronation demonstrated more increased ankle/rear-foot dorsiflexion when measured with the STJ in pronation than the group who performed the 3-wk stretching program with the STJ positioned in supination. No significant main effect of stretching group or interaction for dorsiflexion at the midfoot was detected (P = .755 and P = .820, respectively).Conclusion:After a 3-wk gastrocnemius-stretching program, when measuring dorsiflexion with the STJ positioned in supination, the participants who completed a 3-wk gastrocnemius stretching program with the STJ positioned in pronation showed more increased dorsiflexion at the ankle/rear foot than participants who completed the stretching program with the STJ positioned in supination.

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