Biomedical subjects

D M Pincivero

Publications and source records attributed to D M Pincivero.

27 records · Page 2Linked to original sources

PubMed1997

Reliability and precision of isokinetic strength and muscular endurance for the quadriceps and hamstrings.

The importance of accurately reproducing isokinetic strength values is critical for the assessment of training induced changes in muscle function. The purpose of this study was to determine the test re-test reliability of the Biodex System 2 Isokinetic Dynamometer for concentric quadricep and hamstring strength and muscular endurance. Twenty-one healthy volunteers underwent isokinetic testing on 2 occasions separated by 7 days. Each subject performed 5 repetitions at 60 degrees/ second followed by a muscular endurance test which consisted of 30 repetitions at 180 degrees/second. The results demonstrated high ICC values ranging from r = 0.88 to r = 0.97 and r = 0.82 to r = 0.96 for variables measured at 60 degrees/second and 180 degrees/second, respectively, SEM values were found to range from low to moderate, 4.8% to 11.6% and 5.6% to 10.8%, at 60 and 180 degrees/second, respectively. ICC coefficients were found to be low, r = 0.52 to r = 0.74, and SEM values were found to be high, 9.8% to 20.8%, for the work fatigue index at 180 degrees/second. The results demonstrate that isokinetic values obtained at 60 and 180 degrees/second are highly reproducible with the Biodex System 2 Dynamometer provided that adequate calibration, gravity correction and patient positioning is recorded and standardized. However, the work fatigue index as a measure of muscular endurance has not been shown to be reliable or precise. Changes in muscular strength over time should be considered valid if these differences lie beyond the SEM values reported in this study.

Adult↗

PubMed1997

Relation between open and closed kinematic chain assessment of knee strength and functional performance.

OBJECTIVE: To assess the relationship between concentric isokinetic quadriceps and hamstring strength values with the single leg hop for distance test, a closed kinematic chain activity. DESIGN: Correlational study. SETTING: Neuromuscular Research Laboratory, University of Pittsburgh. PARTICIPANTS: Subjects for this study consisted of 37 college-aged volunteers (21 men, 16 women: mean age = 22.76 +/- 3.52 years, height = 169.90 +/- 10.60 cm, weight = 69.31 +/- 14.60 kg) with no previous history of injury to the lower extremity. INTERVENTION: Each subject performed three trials of a single leg hop for distance test for the dominant and nondominant limbs followed by isokinetic evaluation. Isokinetic strength was assessed with the Biodex System II Isokinetic Dynamometer (Biodex Medical Inc., Shirley, NY, U.S.A.) for the quadriceps and hamstrings at preset angular velocities of 60 degrees/s (5 repetitions) and 180 degrees/s (30 repetitions). Before testing, each subject completed a dynamic warm-up period that consisted of submaximal cycling at a fixed cadence of 60 revolutions/min followed subsequently by quadriceps and hamstring muscle stretching. MAIN OUTCOME MEASURES: The distance hopped in centimeters was converted to a ratio of the distance hopped to the individual leg length measured from the anterior superior iliac spine to the medial malleolus. Isokinetic values were obtained for peak torque (Nm), peak torque/body weight (%), total work (Nm), and average power (W). MAIN RESULTS: Low to moderate significant relationships were found to exist between the single leg hop for distance test and the isokinetic variables for the quadriceps and hamstrings of both limbs at each test velocity. Significant correlation coefficients ranged from r = 0.33 to r = 0.69 at 60 degrees/s and r = 0.33 and r = 0.67 at 180 degrees/s. Correlation coefficients were found to be statistically greater for the hamstrings than the quadriceps for total work and average power at 60 degrees/s and for peak torque/body weight, total work, and average power at 180 degrees/s (p < 0.05). CONCLUSIONS: Concentric quadriceps and hamstring strength seem to demonstrate a significant contribution to the single leg nop for distance test; however, the hamstring muscles may play a more important role during the propulsive phase, thereby enabling subjects to jump further.

Adult↗

PubMed1997

Effects of rest interval on isokinetic strength and functional performance after short-term high intensity training.

OBJECTIVES: The ability to maximally generate active muscle tension during resistance training has been established to be a primary determinant for strength development. The influence of intrasession rest intervals may have a profound effect on strength gains subsequent to short-term high intensity training. The purpose of this study was to examine the effects of rest interval on strength and functional performance after four weeks of isokinetic training. METHODS: Fifteen healthy college aged individuals were randomly assigned to either a short rest interval group (group 1, n = 8) or a long rest interval group (group 2, n = 7). Subjects were evaluated for quadriceps and hamstring isokinetic strength at 60 (five repetitions) and 180 (30 repetitions) degrees/second and functional performance with the single leg hop for distance test. One leg of each subject was randomly assigned to a four week, three days/week isokinetic strength training programme for concentric knee extension and flexion performed at 90 degrees/second. Subjects in group 1 received a 40 second rest interval in between exercise sets, whereas subjects in group 2 received a 160 second rest period. RESULTS: A two factor analysis of variance for the pre-test--post-test gain scores (%) showed significantly greater improvements for isokinetic hamstring total work and average power at 180 degrees/second for the trained limb of subjects in group 2 than their contralateral non-trained limb and the subjects in group 1. Significantly greater improvements for the single leg hop for distance were also found for the trained limbs of subjects in both groups as compared with the non-trained limbs. CONCLUSIONS: The findings indicate that a relatively longer intrasession rest period resulted in a greater improvement in hamstring muscle strength during short term high intensity training.

Adult↗

PubMed1997

A physiological review of American football.

American football has been one of the most popular sports in North America within the past century and has recently received support and increased participation from European nations. Two of the biggest concerns regarding participation in American football are the high incidence of injury and the physical demand for preparation. A basic understanding of the physiological systems utilised in the sport of football is necessary in order to develop optimal training programmes geared specifically for preparation as well as the requirements of individual field positions. Previously, it has been assumed that football relies primarily on an anaerobic source of energy for adenosine triphosphate (ATP) resynthesis with approximately 90% coming from the phosphocreatine (PCr) energy system. In lieu of research conducted specifically with football players, it appears that the energy contribution from the anaerobic glycolytic pathway in this sport has been underestimated. The elevated blood lactate levels observed in football players following game participation cast doubt on this hypothesis. Identifying position specific characteristics may also enhance the development of training programmes based on the requirements of the different positions. It appears that offensive and defensive linemen are generally larger, have higher levels of percent body fat and have greater absolute strength scores than all other positions. Offensive backs, defensive backs and wide receivers tend to display the lowest percentages of body fat, lower absolute strength scores, fastest times over 5, 10, 40 and 300m and the highest relative VO2max values. Linebackers appeared to represent a transition group mid way between the backs and linemen for size, body composition, strength, speed and endurance as well as positional duties. Findings within the literature suggest that a lack of cardiovascular development of university and professional football players may prove to be a hindrance to performance with specific regards to thermal regulation. Additional aerobic conditioning as well as the reduction of percent body fat would not only enhance performance, but might play a key role in preventing injuries and allowing a smoother transition into life after football.

Body Composition↗

PubMed1997

The effect of sudden inversion stress on EMG activity of the peroneal and tibialis anterior muscles in the chronically unstable ankle.

Residual symptoms resulting from recurrent episodes of inversion-type ankle sprains may be attributed to a decreased neuromuscular response of the peroneal or tibialis anterior muscles, thereby increasing the probability for reinjury. The purpose of this study was to examine the electromyographic (EMG) response time of the peroneal and tibialis anterior muscles in response to sudden plantar flexion/inversion stress in the chronically functional unstable and normal ankle. Subjects for this study consisted of 13 athletically active individuals (five males and eight females, mean age = 19.2 +/- 1.51 years) with a previous history of a unilateral inversion-type ankle sprain. A specially designed platform that allows each foot to drop into plantar flexion/inversion from a standing neutral position was used. Reaction time in milliseconds for the peroneal and tibialis anterior muscles to sudden plantar flexion/inversion was measured via surface EMG. A paired t test was performed with the Bonferroni-Dunn correction factor to determine differences between the peroneal and tibialis anterior as well as between the chronically unstable and contralateral normal ankle. The results indicated no significant differences between the stable and unstable ankles for the peroneal or the tibialis anterior muscles. The results also indicated no significant differences existed between the tibialis anterior and peroneal muscles in either the stable or unstable ankles. The findings from the present study suggest that self-reported functional ankle instability may not result in a diminished reflex response time of the peroneal and tibialis anterior muscles to sudden plantar flexion/inversion stress.

Adult↗

PubMed1994

Medial elbow stability. Clinical implications.

Medial elbow injuries of athletes, such as baseball pitchers and javelin throwers, can prove to be debilitating and may have a negative effect on performance. The most significant injury to the elbow occurs is an ulnar collateral ligament (UCL) sprain or rupture, which compromises the medial stability of the elbow joint. It has been found that the anterior oblique portion of the UCL is the primary stabiliser of the elbow, and that trauma to this complex may significantly hinder normal elbow function. An accurate diagnosis will dictate the degree of injury to the elbow as well as determine the most appropriate means of treatment.

Athletic Injuries↗

PubMed1994

The effects of a functional elbow brace on medial joint stability: a case study.

Medical elbow ligament sprains in athletics can be traumatic and disabling. In this case report, we outline the effect of a prototype functional elbow brace on joint stability in a female collegiate javelin thrower with an ulnar collateral ligament sprain. A valgus force to both elbows was applied using graded stress radiography (Telos GA-II/E stress device) at 0, 5, 10, and 15 kiloPascals (kPa) of pressure. The increase in gap width between the coronoid process and the medial epicondyle was measured from anteroposterior radiographs to determine medial displacement. The brace resulted in less displacement in both injured and noninjured ulnar collateral ligament; injured ulnar collateral ligament demonstrated greater displacement regardless of condition. The brace restored medial stability to the elbow joint by 49%, 38%, and 35% at 5, 10, and 15 kPa of pressure, respectively. The application of the brace may be useful in athletes with ulnar collateral ligament injuries.

Journal Article↗

PubMedDate not supplied

The role of proprioception in the management and rehabilitation of athletic injuries.

Rehabilitation continues to evolve with the increased emphasis on patient management and proprioceptive training. Proprioception can be defined as a specialized variation of the sensory modality of touch that encompasses the sensation of joint movement (kinesthesia) and joint position (joint position sense). Numerous investigators have observed that afferent feedback to the brain and spinal pathways is mediated by skin, articular, and muscle mechanoreceptors. Examining the effects of ligamentous injury, surgical intervention, and proprioceptively mediated activities in the rehabilitation program provides an understanding of the complexity of this system responsible for motor control. It appears that this neuromuscular feedback mechanism becomes interrupted with injury and abnormalities, and approaches restoration after surgical intervention and rehabilitation. Rehabilitation programs should be designed to include a proprioceptive component that addresses the following three levels of motor control: spinal reflexes, cognitive programming, and brainstem activity. Such a program is highly recommended to promote dynamic joint and functional stability. Thus far, current knowledge regarding the basic science and clinical application of proprioception has led the profession of sports medicine one step closer to its ultimate goal of restoring function.

Adaptation, Physiological↗

PubMedDate not supplied

Neuromuscular activation and RPE in the quadriceps at low and high isometric intensities.

INTRODUCTION: The purpose of this study was to examine neuromuscular activation and ratings of perceived exertion (RPE) at 10% and 80% quadriceps MVC in healthy males. METHODS: Seventeen college-aged volunteers (mean age = 22.6 years, mean height = 178.9 cm, mean weight = 78.8 kg) were assessed for isometric EMG activity of the vastus medialis (VM) and vastus lateralis (VL) at 10% and 80% MVC, and RPE at 80% MVC. Perceived exertion was measured with a modified category ratio scale (CR-10) and was anchored with 1 high and 1 low anchor. Raw EMG signals were sampled via telemetry (rate = 1,000 Hz) and integrated (3 sec) for each contraction for each muscle (bandpass = 16-500 Hz, CMRR = 130 dB). A one-sample t-test was performed for each variable and 95% confidence intervals were calculated. RESULTS: Means and CI for each variable are as follows: 10% MVC VM IEMG (t16 = 5.05, p < 0.001, .95 CI = 3.11 +/- 1.3), 80% MVC VM IEMG (t16 = 22.51, p < 0.001, .95 CI = 73.2 +/- 6.89), 10% MVC VL IEMG (t16 = 8.10, p < 0.001, .95 CI = 9.41 +/- 2.47), 80% MVC VL IEMG (t16 = 39.56, p < 0.001, .95 CI = 87.32 +/- 4.68), and 80% MVC RPE (t16 = 11.85, p < 0.001, .95 CI = 5.24 +/- 0.93). DISCUSSION: The major findings illustrate an apparent underestimation of RPE at 80% MVC for the quadriceps. Neuromuscular activation appears to be lower than the expected force output at both intensities for the VM while VL activation corresponded closely at 10% MVC and was higher at 80% MVC.

Adult↗