Context:The combined effects of strength and proprioception training, especially in individuals w... more Context:The combined effects of strength and proprioception training, especially in individuals with ankle instability, have not been studied extensively.Objective:To examine the influence of 6 weeks of strength and proprioception training on measures of muscle fatigue and static balance in those with unilateral functional ankle instability (FAI).Design:Pretest–posttest, randomized groups.Setting:A climate-controlled sports-medicine research laboratory.Subjects:38 subjects with self-reported unilateral FAI.Measurements:Muscle fatigue was determined using the median power frequency (fmed) from an electromyographic signal, and static balance was assessed using center-of-pressure values obtained from a triaxial force plate.Results:There were no significant effects of the strength or proprioception training on our measures of muscle fatigue and static balance.Conclusions:Strength training, proprioception training, and the combination of the 2 failed to improve postural-stability charact...
Objective: To determine the reliability of 2 common measures of proprioception. Design and Settin... more Objective: To determine the reliability of 2 common measures of proprioception. Design and Setting: Joint position sense (JPS) and force reproduction (FR) were measured in the dominant shoulder using internal-rotation (IR) and external-rotation (ER) target angles on 2 consecutive days. Subjects: Thirty-one healthy subjects (age ϭ 22.0 Ϯ 2.8 years, height ϭ 171.8 Ϯ 9.2 cm, mass ϭ 69.5 Ϯ 15.9 kg) who did not regularly compete in overhand sports volunteered to participate in the study. Measurements: Error scores were calculated at 2 target angles by averaging the absolute difference of 3 trials of JPS and FR. Reliability was determined by comparing the error scores obtained on 2 consecutive days. Results: The inclinometer was found to be a reliable instrument as both intertester (.999) and intratester (.999) intraclass correlation coefficients were high. The JPS and FR measurements were also found to be reliable, with intraclass correlation coefficients ranging from .978 to .984. No differences were observed between trials for either measure. Conclusions: The inclinometer was a reliable instrument and can provide an affordable and accurate measure of range of motion and JPS. Both JPS and FR were also reliable measures of proprioception in the shoulder. Further research is needed to identify the specific mechanism of proprioception during these tasks.
Concussion management has become an area of great concern in athletics, and neurocognitive test... more Concussion management has become an area of great concern in athletics, and neurocognitive tests, such as Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT), are commonly used as management tools. Given the restrictive nature of current management plans, anecdotal concerns have been raised about athletes trying to cheat the assessments and return to participation sooner. Stimulants have been shown to improve neurocognitive measures similar to those used in ImPACT. Therefore, they could possibly improve performance during baseline and postinjury testing. To examine the effects of a supplement containing stimulants on ImPACT performance. Crossover study. Research laboratory. A total of 5 men (age = 20.6 ± 1.5 years, height = 176.3 ± 9.6 cm, mass = 76.9 ± 18.6 kg) and 7 women (age = 20.6 ± 1.1 years, height = 162.9 ± 7.8 cm, mass = 60.9 ± 8.2 kg) with no histories of physician-diagnosed head injury, learning disability, or attention-deficit disorder. Partic...
Anabolic steroid precursors have gained widespread popularity as ergogenic supplements. Advertise... more Anabolic steroid precursors have gained widespread popularity as ergogenic supplements. Advertisements for these supplements claim that they increase endogenous testosterone production and protein synthesis, resulting in increased lean body mass and strength during training. At this time scientific support is limited, but the potential for serious side effects exists and the popularity of these supplements continues to grow. This review provides rationales for the ergogenic claims regarding steroid precursors and compares claims with data from scientifically controlled investigations. A search of MEDLINE and SPORT Discus from 1960 to 2001 using the key words dehydroepiandrosterone, androstenedione, and androstenediol in combination with testosterone, estrogen, exercise, performance, and side effects. Although fairly new to the athletic community, steroid precursors have been used as ergogenic or anabolic agents for quite some time. Suggested gains in strength and lean body mass are ...
OBJECTIVE: To compare the effects of an isokinetic fatigue protocol and a functional fatigue prot... more OBJECTIVE: To compare the effects of an isokinetic fatigue protocol and a functional fatigue protocol on time to stabilization (TTS), ground reaction force (GRF), and joint kinematics during a jump landing. DESIGN AND SETTING: Subjects were assessed on 2 occasions for TTS, GRF, and joint kinematics immediately before and after completing a fatigue protocol. One week separated the 2 sessions, and the order of fatigue protocols was randomly assigned and counterbalanced. SUBJECTS: Twenty healthy male (n = 8, age = 21.8 +/- 1.4 years, height = 180.6 +/- 7.6 cm, and mass = 74.1 +/- 13.0 kg) and female (n = 12, age = 22.2 +/- 2.1 years, height = 169.3 +/- 9.8 cm, and mass = 62.5 +/- 10.1 kg) subjects volunteered to participate. MEASUREMENTS: Subjects performed 2-legged jumps equivalent to 50% of maximum jump height, followed by a single-leg landing onto the center of a forceplate 70 cm from the starting position. Peak vertical GRF and vertical, medial-lateral, and anterior-posterior TTS w...
OBJECTIVE: To determine if there were differences in concentric peak torque/body-weight (PT/BW) r... more OBJECTIVE: To determine if there were differences in concentric peak torque/body-weight (PT/BW) ratios and concentric time to peak torque (TPT) of the dorsiflexors and evertors in uninjured and functionally unstable ankles using a stretch-shortening cycle (SSC) protocol on an isokinetic dynamometer. DESIGN AND SETTING: We employed a case-control study design to examine the test subjects in a climate-controlled athletic training/sports medicine research laboratory. SUBJECTS: Thirty subjects volunteered to participate in this study, 15 with unilateral functional ankle instability and 15 matched controls. MEASUREMENTS: Participants were assessed isokinetically using an SSC protocol for the dorsiflexors and evertors at 120 and 240 degrees.s(-1), bilaterally. Strength was assessed using PT values normalized for body mass. Concentric TPT measurements were also compared between the groups. RESULTS: No differences in concentric PT/BW ratios or concentric TPT were evident between the groups ...
There have been reports of overhand throwing athletes having decreased joint position sense in th... more There have been reports of overhand throwing athletes having decreased joint position sense in their dominant shoulder as compared with the nondominant shoulder. Very little research, however, exists concerning joint position sense in the female athlete. Female softball athletes have decreased joint position sense in their dominant shoulder as compared with their nondominant shoulder. Factorial design with investigation of multiple independent variables. Joint position sense was assessed in 50 female softball players and 50 nonthrowing female athletes by using an inclinometer during four glenohumeral joint motions. Both the dominant and nondominant shoulders were assessed and error scores were calculated to describe joint position sense. Data were collected during the course of a fall semester and analyzed by using a mixed model analysis of variance with repeated measures on the dependent variable (error scores). A significant group by movement interaction was observed, with the sof...
Spine-Board Transfer Techniques and the Unstable Cervical Spine
Spine, 2004
A repeated-measures design using a cadaveric model was used in this preliminary investigation on ... more A repeated-measures design using a cadaveric model was used in this preliminary investigation on the effectiveness of spine-board transfer techniques. To compare the amount of angulation (flexion-extension) motion that results at the cervical spine during the execution of the log-roll maneuver and the lift-and-slide technique; and to examine how changes to the integrity of the cervical spine impacts the amount of motion generated during the transfer process. Very little research has been performed to establish the efficacy of spine-board transfer techniques. Early studies have indicated that the log-roll maneuver may not be appropriate for transferring victims with thoracolumbar injuries. Also, there has not been a single study that has reported the impact of transfer techniques on the unstable cervical spine. This lack of data necessitated the present study. Four groups (with six participants each) were asked to execute the log-roll maneuver and the lift-and-slide technique on five cadavers. An electromagnetic motion analysis device was used to assess the amount of angulation motion generated at the C5-C6 segment during the execution of these transfer techniques. To examine how changes to the integrity of the cervical spine impacts the amount of motion that is produced during the transfer process, flexion-extension motion was assessed under various conditions: across a stable C5-C6 segment, after the creation of a posterior ligamentous injury, and after a complete segmental injury. No significant differences in angulation motion were noted between transfer techniques. However, significant differences were noted between all three injury conditions. That is, as the severity of the injury increased, the average amount of angulation motion produced at the site of the lesion also increased, regardless of technique. The participants of this study were able to restrict flexion-extension motion equally well with thelog-roll maneuver as with the lift-and-slide technique. However, more research is needed to fully ascertain the effectiveness of spine-board transfer techniques.
Measurement of glenohumeral joint laxity using the KT-2000 knee ligament arthrometer: Reliability analysis
Physical Therapy in Sport, 2006
... Herling, & Manzour (2001), we investigated subjects in a position which better approx... more ... Herling, & Manzour (2001), we investigated subjects in a position which better approximates what has been described by previous researchers as a position that manifests instability (Glousman et al., 1988; Kronberg et al., 1991; O'Connell, Nuber, Mileski, & Lautenschlager ...
The Effects of Gamma Aminobutyric Acid on Growth Hormone Secretion at Rest and Following Exercise
Medicine & Science in Sports & Exercise, 2003
Daily Changes in Fluid Distribution Using Multifrequency Bioimpedance Analysis and the Effects of Body Position
Medicine & Science in Sports & Exercise, 2002
Eversion and Inversion Strength Ratios in Subjects with Unilateral Functional Ankle Instability
Medicine & Science in Sports & Exercise, 2001
Growth Hormone Isoform Responses to GABA Ingestion at Rest and after Exercise
Medicine & Science in Sports & Exercise, 2008
Oral administration of the amino acid/inhibitory neurotransmitter gamma aminobutyric acid (GABA) ... more Oral administration of the amino acid/inhibitory neurotransmitter gamma aminobutyric acid (GABA) reportedly elevates resting serum growth hormone (GH) concentrations. To test the hypothesis that GABA ingestion stimulates immunoreactive GH (irGH) and immunofunctional GH (ifGH) release at rest and that GABA augments the resistance exercise-induced irGH/ifGH responses. Eleven resistance-trained men (18-30 yr) participated in this randomized, double-blind, placebo-controlled, crossover study. During each experimental bout, participants ingested either 3 g of GABA or sucrose placebo (P), followed either by resting or resistance exercise sessions. Fasting venous blood samples were acquired immediately before and at 15, 30, 45, 60, 75, and 90 min after GABA or P ingestion and were assayed for irGH and ifGH. At rest, GABA ingestion elevated both irGH and ifGH compared with placebo. Specifically, peak concentrations of both hormones were elevated by about 400%, and the area under the curve (AUC) was elevated by about 375% (P < 0.05). Resistance exercise (EX-P) elevated time-point (15-60 min) irGH and ifGH concentrations compared with rest (P < 0.05). The combination of GABA and resistance exercise (EX-GABA) also elevated the peak, AUC, and the 15- to 60-min time-point irGH and ifGH responses compared with resting conditions (P < 0.05). Additionally, 200% greater irGH (P < 0.01) and 175% greater ifGH (P < 0.05) concentrations were observed in the EX-GABA than in the EX-P condition, 30 min after ingestion. GABA ingestion did not alter the irGH to ifGH ratio, and, under all conditions, ifGH represented approximately 50% of irGH. Our data indicate that ingested GABA elevates resting and postexercise irGH and ifGH concentrations. The extent to which irGH/ifGH secretion contributes to skeletal muscle hypertrophy is unknown, although augmenting the postexercise irGH/ifGH response may improve resistance training-induced muscular adaptations.
Objective: To characterize the diagnosis of pancreatic trauma in an athletic population and to ra... more Objective: To characterize the diagnosis of pancreatic trauma in an athletic population and to raise awareness among health care providers of the possibility of this life- and organ-threatening injury. Background: An 18-year-old, previously healthy female collegiate soccer athlete sustained a direct blow from an opponent's knee between the left and right upper abdominal quadrants while attempting to head the ball. She initially presented with only minimal nausea and discomfort, but this progressed to abdominal pain, tenderness, spasm, and vomiting. She was referred to the emergency department, where she was diagnosed with a pancreatic laceration. Differential Diagnosis: Duodenal, hepatic, or splenic contusion or laceration; hemorrhagic ovarian cyst. Treatment: The patient underwent a distal pancreatectomy and total splenectomy. Uniqueness: Pancreatic injuries, particularly those severe enough to warrant surgical intervention, are extremely rare in athletes. Conclusions: Recognit...
Your browser version may not work well with NCBI's web applications. More information here..... more Your browser version may not work well with NCBI's web applications. More information here... ...
Objectives: To examine the effect of six weeks of strength and proprioception training on eversio... more Objectives: To examine the effect of six weeks of strength and proprioception training on eversion to inversion isokinetic strength ratios (E/I ratios) in subjects with unilateral functional ankle instability. Methods: Thirty eight subjects were randomly assigned to one of four treatment groups: strength training (S); proprioception training (P); strength + proprioception training (B); control (C). Isokinetic strength was tested before and after training using a Kin Com 125 automatic positioning isokinetic dynamometer. Subtalar joint eversion and inversion motions were tested both concentrically and eccentrically through a range of motion involving 40°. All peak torque and average torque values were normalised for body mass. E/I ratios were calculated from average torque and peak torque measures by taking the concentric eversion value and combining it with the eccentric inversion value. Data were analysed using a mixed model analysis of variance with repeated measures on the test factor. Average torque and peak torque E/I ratios at 30 and 120°/s were analysed separately. Results: There were no significant differences in average torque and peak torque E/I ratios of the functionally unstable ankle for any of the groups after training compared with before. Conclusions: Six weeks of strength and proprioception training (either alone or combined) had no effect on isokinetic measures of strength in subjects with self reported unilateral functional instability. Further studies examining this agonist (concentric) to antagonist (eccentric) muscle group strength ratio are needed.
Archives of Physical Medicine and Rehabilitation, 2004
Objective: To determine the effects of a cryotherapy treatment on shoulder proprioception. Design... more Objective: To determine the effects of a cryotherapy treatment on shoulder proprioception. Design: Crossover design with repeated measures. Setting: University athletic training and sports medicine research laboratory. Participants: Thirty healthy subjects (15 women, 15 men). Intervention: A 30-minute cryotherapy treatment. Main Outcome Measures: Joint position sense was measured in the dominant shoulder by using an inclinometer before and after receiving 30 minutes of either no ice or a 1-kg ice bag application. Skin temperature was measured below the tip of the acromion process and recorded every 5 minutes for the entire 30 minutes and immediately after testing. Three different types of error scores were calculated for data analyses and used to determine proprioception. Results: Separate analyses of absolute, constant, and variable error failed to identify changes in shoulder joint proprioception as a function of the cryotherapy application. Conclusions: Application of an ice bag to the shoulder does not impair joint position sense. The control of proprioception at the shoulder may be more complex than at other joints in the body. Clinical implications may involve modifying rehabilitation considerations when managing shoulder injuries.
Uploads
Papers by Michael Powers