Effects of Core-Musculature Fatigue on Maximal Shoulder Strength

2015 ◽  
Vol 24 (4) ◽  
pp. 384-390 ◽  
Author(s):  
James R. Rosemeyer ◽  
Bradley T. Hayes ◽  
Craig L. Switzler ◽  
Charlie A. Hicks-Little
Keyword(s):  
Upper Extremity ◽  
Outcome Measures ◽  
Sports Medicine ◽  
Sagittal Plane ◽  
Statistical Significance ◽  
Strength Test ◽  
Core Stability ◽  
Medicine Research ◽  
The Core ◽  
Shoulder Strength

Context:Core stability has been shown to affect lower-extremity motion, but activation of the core has also been observed just before movements of the upper extremity. However, there is limited evidence regarding the effects that core musculature has on upper-extremity strength.Objective:To determine the effects of core fatigue on maximal shoulder strength.Design:Crossover study.Setting:Sports-medicine research laboratory.Participants:23 participants (15 male and 8 female, age 21.3 ± 2.5 y, height 174.5 ± 10.3 cm, weight 71.3 ± 12.0 kg).Intervention:All participants performed maximal voluntary isometric contractions in 3 different planes (sagittal, frontal, transverse) of shoulder-joint motion. A core-fatiguing protocol was conducted, and the same 3 shoulder-strength tests were repeated and compared with the initial measurements.Main Outcome Measures:Strength measures were recorded in kilograms with a dynamometer.Results:Results showed a significant decrease in strength in the frontal (−0.56 ± 1.06 kg, P = .020) and transverse (−0.89 ± 1.49 kg, P = .012) planes but not in the sagittal plane (−0.20 ± 0.98 kg, P > .05). Furthermore, regardless of the specific strength test measured, results revealed that the 1st (−7.05% ± 11.65%, P = .012) and 2nd (−5.71% ± 12.03%, P = .042) strength-test measurements after the fatiguing protocol were significantly decreased, while the 3rd strength-test measurement (−4.19% ± 12.48%, P = .140) did not show statistical significance.Conclusion:These results indicate that decrease in core stability may have an influence on shoulder strength. The literature suggests that the core is designed for endurance, and this study helps validate its recovery properties. Further research is needed to determine the significance of this effect and how injury rates coincide.

Correlation Between Ankle-Dorsiflexion and Hip-Flexion Range of Motion and the Functional Movement Screen Hurdle-Step Score

2017 ◽  
Vol 26 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Jacob J. Janicki ◽  
Craig L. Switzler ◽  
Bradley T. Hayes ◽  
Charlie A. Hicks-Little
Keyword(s):  
Range Of Motion ◽  
Outcome Measures ◽  
Sports Medicine ◽  
Strong Relationship ◽  
Ankle Dorsiflexion ◽  
Functional Movement ◽  
Medicine Research ◽  
Movement Screening ◽  
And Performance ◽  
Hip Flexion

Context:Functional movement screening (FMS) has been gaining popularity in the fields of sports medicine and performance. Currently, limited research has examined whether FMS screening that identifies low FMS scores is attributed primarily to limits in range of motion (ROM).Objective:To compare scores from the FMS hurdle-step movement with ROM measurements for ankle dorsiflexion and hip flexion (HF).Design:Correlational research design.Setting:Sports medicine research laboratory.Participants:20 healthy active male (age 21.2 ± 2.4 y, weight 77.8 ± 10.2 kg, height 180.8 ± 6.8 cm) and 20 healthy active female (21.3 ± 2.0 y, 67.3 ± 8.9 kg, 167.4 ± 6.6 cm) volunteers.Intervention:All 40 participants completed 3 trials of the hurdle-step exercise bilaterally and goniometric ROM measurements for active ankle dorsiflexion and HF.Main Outcome Measures:Correlations were determined between ROM and FMS scores for right and left legs. In addition, mean data were compared between FMS scores, gender, and dominant and nondominant limbs.Results:There were no significant correlations present when all participants were grouped. However, when separated by gender significant correlations were identified. There was a weak correlation with HF and both hurdle-step (HS) and average hurdle-step (AHS) scores on both left (r = .536, P = .015 and r = .512, P = .012) and right (r = .445, P = .049 and r = .565, P = .009) legs for women. For men, there was a poor negative correlation of HF and both HS and AHS on the left leg (r = –.452, P = .045 and r = .451, P = .046).Conclusion:Our findings suggest that although hip and ankle ROMs do not have a strong relationship with FMS hurdle-step scores, they are a contributing factor. More research should be conducted to identify other biomechanical factors that contribute to individual FMS test scores.

Fatigue’s Effect on Eversion Force Sense in Individuals With and Without Functional Ankle Instability

2012 ◽  
Vol 21 (2) ◽  
pp. 127-136 ◽  
Author(s):  
Cynthia J. Wright ◽  
Brent L. Arnold
Keyword(s):  
Outcome Measures ◽  
Repeated Measures ◽  
Sports Medicine ◽  
Ankle Instability ◽  
Absolute Error ◽  
Ankle Sprains ◽  
Functional Ankle Instability ◽  
Maximal Voluntary Isometric Contraction ◽  
Medicine Research ◽  
Force Sense

Context:Force sense (FS), the proprioceptive ability to detect muscle-force generation, has been shown to be impaired in individuals with functional ankle instability (FAI). Fatigue can also impair FS in healthy individuals, but it is unknown how fatigue affects FS in individuals with FAI.Objective:To assess the effect of fatigue on ankle-eversion force-sense error in individuals with and without FAI. Design: Case control with repeated measures.Setting:Sports medicine research laboratory.Participants:32 individuals with FAI and 32 individuals with no ankle sprains or instability in their lifetime. FAI subjects had a history of ≥1 lateral ankle sprain and giving-way ≥1 episode per month.Interventions:Three eversion FS trials were captured per load (10% and 30% of maximal voluntary isometric contraction) using a load cell before and after a concentric eversion fatigue protocol.Main Outcome Measures:Trial error was the difference between the target and reproduction forces. Constant error (CE), absolute error (AE), and variable error (VE) were calculated from 3 trial errors. A Group × Fatigue × Load repeated-measures ANOVA was performed for each error.Results:There were no significant 3-way interactions or 2-way interactions involving group (all P > .05). CE and AE had a significant 2-way interaction between load and fatigue (CE: F1,62 = 8.704, P = .004; AE: F1,62 = 4.024, P = .049), and VE had a significant main effect for fatigue (F1,62 = 5.130, P = .027), all of which indicated increased FS error with fatigue at 10% load. However, at 30% load only VE increased with fatigue. The FAI group had greater error as measured by AE (F1,62 = 4.571, P = .036) but not CE or VE (P > .05).Conclusions:Greater AE indicates that FAI individuals are less accurate in their force production. Fatigue impaired force sense in all subjects equally. These deficits provide evidence of impaired proprioception with fatigue and in individuals with FAI.

Lack of Neuromuscular Origins of Adaptation After a Long-Term Stretching Program

2012 ◽  
Vol 21 (2) ◽  
pp. 99-106 ◽  
Author(s):  
Bradley T. Hayes ◽  
Rod A. Harter ◽  
Jeffrey J. Widrick ◽  
Daniel P. Williams ◽  
Mark A. Hoffman ◽  
...  
Keyword(s):  
Outcome Measures ◽  
Repeated Measures ◽  
Sports Medicine ◽  
Reciprocal Inhibition ◽  
Ankle Dorsiflexion ◽  
Controlled Study ◽  
Static Stretching ◽  
Reflex Pathway ◽  
Medicine Research

Context:Static stretching is commonly used during the treatment and rehabilitation of orthopedic injuries to increase joint range of motion (ROM) and muscle flexibility. Understanding the physiological adaptations that occur in the neuromuscular system as a result of long-term stretching may provide insight into the mechanisms responsible for changes in flexibility.Objective:To examine possible neurological origins and adaptations in the Ia-reflex pathway that allow for increases in flexibility in ankle ROM, by evaluating the reduction in the synaptic transmission of Ia afferents to the motoneuron pool.Design:Repeated-measures, case-controlled study.Setting:Sports medicine research laboratory.Participants:40 healthy volunteers with no history of cognitive impairment, neurological impairment, or lower extremity surgery or injury within the previous 12 mo.Intervention:Presynaptic and postsynaptic mechanisms were evaluated with a chronic stretching protocol. Twenty subjects stretched 5 times a wk for 6 wk. All subjects were measured at baseline, 3 wk, and 6 wk.Main Outcome Measures:Ankle-dorsiflexion ROM, Hmax:Mmax, presynaptic inhibition, and disynaptic reciprocal inhibition.Results:Only ROM had a significant interaction between group and time, whereas the other dependent variables did not show significant differences. The experimental group had significantly improved ROM from baseline to 3 wk (mean 6.2 ± 0.9, P < .001), 3 wk to 6 wk (mean 5.0 ± 0.8, P < .001), and baseline to 6 wk (mean 11.2 ±0.9, P < .001).Conclusions:Ankle dorsiflexion increased by 42.25% after 6 wk of static stretching, but no significant neurological changes resulted at any point of the study, contrasting current literature. Significant neuromuscular origins of adaptation do not exist in the Ia-reflex-pathway components after a long-term stretching program as currently understood. Thus, any increases in flexibility are the result of other factors, potentially mechanical changes or stretch tolerance.

Effects of a Single-Task Versus a Dual-Task Paradigm on Cognition and Balance in Healthy Subjects

2011 ◽  
Vol 20 (3) ◽  
pp. 296-310 ◽  
Author(s):  
Luke M. Ross ◽  
Johna K. Register-Mihalik ◽  
Jason P. Mihalik ◽  
Karen L. McCulloch ◽  
William E. Prentice ◽  
...  
Keyword(s):  
Outcome Measures ◽  
Dual Task ◽  
Sports Medicine ◽  
Healthy Subjects ◽  
Auditory Task ◽  
Balance Performance ◽  
Medicine Research ◽  
Eyes Closed ◽  
Paired Samples ◽  
Task Conditions

Context:Recent evidence has revealed deficiencies in the ability to divide attention after concussion.Objective:To examine the effects of a single vs a dual task on cognition and balance in healthy subjects and to examine reliability of 2 dual-task paradigms while examining the overall feasibility of the tasks.Design:Pretest–posttest experimental design.Setting:Sports medicine research laboratory.Patients:30 healthy, recreationally active college students.Intervention:Subjects performed balance and cognitive tasks under the single- and dual-task conditions during 2 test sessions 14 d apart.Main Outcome Measures:The procedural reaction-time (PRT) test of the Automated Neuropsychological Assessment Metrics (eyes-closed tasks) and an adapted Procedural Auditory Task (PAT; eyes-open tasks) were used to assess cognition. The NeuroCom Sensory Organization Test (SOT) and the Balance Error Scoring System (BESS) were used to assess balance performance. Five 2-way, within-subject ANOVAs and a paired-samples t test were used to analyze the data. ICCs were used to assess reliability across 2 test sessions.Results:On the SOT, performance significantly improved between test sessions (F1,29 = 35.695, P < .001) and from the single to the dual task (F1,29 = 9.604, P = .004). On the PRT, performance significantly improved between test sessions (F1,29 = 57.252, P < .001) and from the single to the dual task (F1,29 = 7.673, P = .010). No differences were seen on the BESS and the PAT. Reliability across test sessions ranged from moderate to poor for outcome measure.Conclusions:The BESS appears to be a more reliable and functional tool in dual-task conditions as a result of its increased reliability and clinical applicability. In addition, the BESS is more readily available to clinicians than the SOT.

scholarly journals Helmet Fit and Cervical Spine Motion in Collegiate Men's Lacrosse Athletes Secured to a Spine Board

2010 ◽  
Vol 45 (3) ◽  
pp. 215-221 ◽  
Author(s):  
Meredith A. Petschauer ◽  
Randy Schmitz ◽  
Diane L. Gill
Keyword(s):  
Cervical Spine ◽  
Range Of Motion ◽  
Sports Medicine ◽  
Sagittal Plane ◽  
Football Players ◽  
Cervical Spine Injuries ◽  
Medicine Research ◽  
Spine Injuries ◽  
Spine Motion ◽  
Spine Board

Abstract Context: Proper management of cervical spine injuries in men's lacrosse players depends in part upon the ability of the helmet to immobilize the head. Objective: To determine if properly and improperly fitted lacrosse helmets provide adequate stabilization of the head in the spine-boarded athlete. Design: Crossover study. Setting: Sports medicine research laboratory. Patients or Other Participants: Eighteen healthy collegiate men's lacrosse players. Intervention(s): Participants were asked to move their heads through 3 planes of motion after being secured to a spine board under 3 helmet conditions. Main Outcome Measure(s): Change in range of motion in the cervical spine was calculated for the sagittal, frontal, and transverse planes for both head-to-thorax and helmet-to-thorax range of motion in all 3 helmet conditions (properly fitted, improperly fitted, and no helmet). Results: Head-to-thorax range of motion with the properly fitted and improperly fitted helmets was greater than in the no-helmet condition (P &lt; .0001). In the sagittal plane, range of motion was greater with the improperly fitted helmet than with the properly fitted helmet. No difference was observed in helmet-to-thorax range of motion between properly and improperly fitted helmet conditions. Head-to-thorax range of motion was greater than helmet-to-thorax range of motion in all 3 planes (P &lt; .0001). Conclusions: Cervical spine motion was minimized the most in the no-helmet condition, indicating that in lacrosse players, unlike football players, the helmet may need to be removed before stabilization.

Performance in Static, Dynamic, and Clinical Tests of Postural Control in Individuals with Recurrent Ankle Sprains

2004 ◽  
Vol 13 (3) ◽  
pp. 255-268 ◽  
Author(s):  
Lyn Nakagawa ◽  
Mark Hoffman
Keyword(s):  
Postural Control ◽  
Outcome Measures ◽  
Sports Medicine ◽  
Center Of Pressure ◽  
Dynamic Balance ◽  
Ankle Sprains ◽  
Clinical Tests ◽  
Balance Test ◽  
Medicine Research ◽  
Balance Tests

Objective:To evaluate postural control in individuals with recurrent ankle sprains with static, dynamic, and clinical balance tests and to examine the relationships between performances in each of these tests.Design:Postural control was evaluated with 3 different balance tests in individuals with and without recurrent ankle sprains.Participants:19 volunteers with recurrent ankle sprains and 19 uninjured control subjects.Interventions:None.Setting:University sports-medicine research laboratory.Main Outcome Measures:Total excursion of the center of pressure (COP) was calculated for the static and dynamic balance tests. Total reach distance was measured for the Star Excursion Balance Test.Results:Subjects with recurrent ankle sprains demonstrated significantly greater excursion of the COP in both the static and dynamic balance tests. Correlations between performances in all tests were very low.Conclusions:Recurrent ankle sprains might be associated with reduced postural control as demonstrated by decreased performance in static and dynamic balance tests.

Assessing Functional Ankle Instability with Joint Position Sense, Time to Stabilization, and Electromyography

2004 ◽  
Vol 13 (2) ◽  
pp. 122-134 ◽  
Author(s):  
Cathleen Brown ◽  
Scott Ross ◽  
Rick Mynark ◽  
Kevin Guskiewicz
Keyword(s):  
Outcome Measures ◽  
Sports Medicine ◽  
Ankle Instability ◽  
Position Sense ◽  
Joint Position Sense ◽  
Joint Position ◽  
Functional Ankle Instability ◽  
Medicine Research ◽  
Recreational Athletes ◽  
Time To Stabilization

Context:Functional ankle instability (FAI) is difficult to identify and quantify.Objective:To compare joint position sense (JPS), time to stabilization (TTS), and electromy-ography (EMG) of ankle musculature in recreational athletes with and without FAI.Design:Case-control compared withttests and ANOVAs.Setting:Sports medicine research laboratory.Participants:20 recreational athletes.Main Outcome Measures:Passive angle reproduction, TTS, and mean EMG amplitude of the tibialis anterior, peroneals, lateral gastrocnemius, and soleus muscles during single-leg-jump landing.Results:No differences in JPS or medial-lateral TTS measures between groups. Significantly longer anterior-posterior TTS (P< .05) in the unstable ankle group. The stable ankle group had significantly higher mean EMG soleus amplitude after landing (P< .05). No other significant differences were found for mean EMG amplitudes before or after landing.Conclusions:Subjects with FAI demonstrated deficits in landing stability and soleus muscle activity during landing that may represent chronic adaptive changes following injury.

scholarly journals Discriminating Between Copers and People With Chronic Ankle Instability

2012 ◽  
Vol 47 (2) ◽  
pp. 136-142 ◽  
Author(s):  
Erik A. Wikstrom ◽  
Mark D. Tillman ◽  
Terese L. Chmielewski ◽  
James H. Cauraugh ◽  
Keith E. Naugle ◽  
...  
Keyword(s):  
Diagnostic Accuracy ◽  
Confidence Intervals ◽  
Outcome Measures ◽  
Sagittal Plane ◽  
Ankle Instability ◽  
Chronic Ankle Instability ◽  
Self Report ◽  
Causal Mechanism ◽  
Diagnostic Utility ◽  
Medicine Research

Context: Differences in various outcome measures have been identified between people who have sprained their ankles but have no residual symptoms (copers) and people with chronic ankle instability (CAI). However, the diagnostic utility of the reported outcome measures has rarely been determined. Identifying outcome measures capable of predicting who is less likely to develop CAI could improve rehabilitation protocols and increase the efficiency of these measures. Objective: To determine the diagnostic utility and cutoff scores of perceptual, mechanical, and sensorimotor outcome measures between copers and people with CAI by using receiver operating characteristic curves. Design: Case-control study. Setting: Sports medicine research laboratory. Patients or Other Participants: Twenty-four copers (12 men, 12 women; age = 20.8 ± 1.5 years, height = 173 ± 11 cm, mass = 78 ± 27 kg) and 24 people with CAI (12 men, 12 women; age = 21.7 ± 2.8 years, height = 175 ± 13 cm, mass = 71 ± 13 kg) participated. Intervention(s): Self-reported disability questionnaires, radiographic images, and a single-legged hop stabilization test. Main Outcome Measure(s): Perceptual outcomes included scores on the Foot and Ankle Disability Index (FADI), FADI-Sport, and a self-report questionnaire of ankle function. Mechanically, talar position was quantified by measuring the distance from the anterior tibia to the anterior talus in the sagittal plane. Sensorimotor outcomes were the dynamic postural stability index and directional indices, which were calculated during a single-legged hop stabilization task. Results: Perceptual outcomes demonstrated diagnostic accuracy (range, 0.79–0.91), with 95% confidence intervals ranging from 0.65 to 1.00. Sensorimotor outcomes also were able to discriminate between copers and people with CAI but with less accuracy (range, 0.69–0.70), with 95% confidence intervals ranging from 0.37 to 0.86. The mechanical outcome demonstrated poor diagnostic accuracy (0.52). Conclusions: The greatest diagnostic utility scores were achieved by the self-assessed disability questionnaires, which indicated that perceptual outcomes had the greatest ability to accurately predict people who became copers after their initial injuries. However, the diversity of outcome measures that discriminated between copers and people with CAI indicated that the causal mechanism of CAI is probably multifactorial.

scholarly journals Relationship between stability and variability of the core in dynamic reaching tasks

2019 ◽  
Author(s):  
Ola Eriksrud ◽  
Jan Cabri ◽  
Peter Federolf
Keyword(s):  
Sagittal Plane ◽  
Pearson Correlation ◽  
Stable Condition ◽  
Frontal Plane ◽  
Core Stability ◽  
Learning Theories ◽  
Movement Speed ◽  
The Core ◽  
Reaching Tasks ◽  
Left And Right

Core stability is important to many functional and athletic tasks. Motion variability has been proposed as a measure to characterize core stability. Based on motor learning theories, the current study hypothesized  that variability and stability of core movements show a U-shaped relationship and further investigated whether functional range of motion (“mobility”) or speed of motion affect this relationship.  Twenty-four healthy subjects performed 20 cycles of two different unilateral hand reaching tasks for both the left and right hand under stable and unstable conditions. Reach targets were positioned to trigger large core movements. Specifically, the anterior target was positioned midsagittal at arm length´s distance and hip height. Two posterior targets (60 degrees posterior to neutral stance frontal plane) on both the left and right side were high (at arm length distance and height with accrued 10 cm) and low (arm length distance at hip height). Kinematic data were recorded and three-dimensional angles between pelvis and thorax (core) were calculated. Pearson correlation coefficients and paired T-tests were calculated to assess variability, mobility and speed of the core movements. A parabolic function was fitted to the variability data and the quality of the fit was assessed by calculating adjusted R-squared values.  In the sagittal plane, variability could be modeled with a U-shaped distribution; in the other planes of motion this was the case in 2 of 4 reaching tests. In two tests, movement speed changed between the stable and unstable conditions. Mobility did not appear to affect variability in the stable condition, but some correlations were observed in the unstable condition. The relationship between mobility and variability, and the change in variability were task-specific.

Mechanical considerations for biomechanical glenohumeral joint modeling

2005 ◽  
Vol 5 (1) ◽  
pp. 29-42
Author(s):  
Krystyna Gielo-Perczak
Keyword(s):  
Upper Extremity ◽  
Sagittal Plane ◽  
Glenohumeral Joint ◽  
Frontal Plane ◽  
Joint Modeling ◽  
Deltoid Muscle ◽  
Limiting Factor ◽  
Joint Stability ◽  
New Information ◽  
Shoulder Strength

The strength of the upper extremity in the frontal plane is two times less than in a sagittal plane. Shoulder strength is a limiting factor in upper extremity exertion capability. The purpose of this study was to analytically explain and present the influence of glenoid curvature and the middle deltoid muscle attachment on vertical translations of a humeral head in the superior-inferior direction during elevated arm positions. The paper reports the magnetic resonance results of the glenoid shape of 12 subjects and confirms variability in tangent inclinations and distances of the tangents from the lateral deltoid attachment. It was found that the largest translations of the humerus are during abduction ranging from 0° to 40° and from 140° to 170°. This suggests that both initiation of a movement and raising an arm above shoulder height are critical. The study confirms that the bone surface contacts as well as the muscles are important factors in stability and joint strength. It may provide new information on the sensitivity of the glenoid shape on glenohumeral joint stability and on individual arm strength.

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