Thermal denaturation of cytochrome c peroxidase: pH dependence.

Upon heating cytochrome c peroxidase (ferrocytochrome c: hydrogen-peroxide oxidoreductase, EC 1.11.1.5) at pH 4 and 5, the enzyme precipitates at 41 degrees C and 51 degrees C, respectively. Incubating the enzyme at lower temperatures causes a slow dissociation of the heme from the protein. The heme precipitates, while the apoprotein remains soluble. Between pH 6 and 8, the native enzyme is converted to a low-spin ferric form upon heating. The Soret maximum shifts from 408 to 414 nm. The midpoint of this transition is pH-dependent, with a value of 46 degrees C at pH 6 decreasing to 29 degrees C at pH 8. At high temperatures the 414 nm form is converted to a species which has a 'free heme' spectrum with low absorptivity and Soret maximum at 390 nm. The midpoint temperature of this latter transition is 62 degrees C and 57 degrees C at pH 7 and 8, respectively.

Effect of bicycle racing saddle design on transcutaneous penile oxygen pressure.

AIM: To determine the reliability of monitoring penile transcutaneous oxygen (tpO2) during cycling, and to assess the influence of seat design and cycling position on tpO2. EXPERIMENTAL DESIGN: repeated measures analysis of the effects of seat design and riding position on tpO2 values. PARTICIPANTS: 31 male cyclists between the ages of 20 and 50 years participated. Subject inclusion criteria were: averaged=or>80 miles of road bicycling per week during the 2 months prior to enrollment in this study; no history of vascular disease, diabetes, or sexual dysfunction; and had an erection within 15 days prior to study. MEASURES: mean tpO2 values were calculated for seated and standing positions using 3 current bicycle seat designs. RESULTS: Test-retest reliability for seated cycling tpO2 values had an ICC (3,1) of 0.76 and mean absolute difference of 5.1 mmHg. Test-retest reliability for standing cycling tpO2 values had an ICC(3,1) of 0.88 and mean absolute difference of 7.23 mmHg. No interaction effect occurred between seat design and position. Seat design had no significant effect on tpO2 values. Seated cycling significantly reduced tpO2 levels compared with standing cycling (P<0.05). Mean percent decreases in tpO2 from standing to seated cycling were; Vetta 76%, Terry 73%, and Specialized 62%. CONCLUSION: The data suggest that penile tpO2 monitoring is reliable for use during cycling studies. None of the seats exhibited any significant ability to spare penile tpO2. The implications of decreased penile tpO2 over different time intervals on penile physiology remain to be investigated.

Effects of recurrent lateral ankle sprains on active and passive judgements of joint position.

The purpose of this study was to examine the effects of recurrent lateral ankle sprains on subjects' active and passive judgments of joint position. Fourteen subjects with recurrent unilateral ankle sprains contributed data to two groups: 1) In Group 1, the subjects' 14 sprained ankles were tested and 2) in Group 2, the same 14 subjects' contralateral nonsprained ankles were tested. An additional seven subjects with no history of injury to either ankle comprised Group 3 with 14 nonsprained control ankles. The experimenter tested all blindfolded subjects with active and passive attempts at replicating predetermined ankle joint positions in the inversion-eversion range of motion. An isokinetic dynamometer measured joint position. A two-way analysis of variance indicated no significant effect caused by ankle injury or noninjury. Passive judgments were significantly better than active judgments of joint position (p less than .01) in the nonsprained control group. The results suggest that joint receptors play a dominant role in joint angle detection and that muscle receptors are more valuable in the perception of joint movement.

Comparison of vastus medialis obliquus: vastus lateralis muscle integrated electromyographic ratios between healthy subjects and patients with patellofemoral pain.

The purpose of this study was to compare vastus medialis obliquus:vastus lateralis muscle (VMO:VL) integrated electromyographic (IEMG) ratios of healthy subjects and patients with unilateral patellofemoral pain (PFP) under isotonic and isometric quadriceps femoris muscle contraction conditions. Subjects ranging in age from 18 to 35 years (mean = 28.06, SD = 5.97) were assigned to one of three groups on the basis of type of knee condition. In group 1, which consisted of seven healthy control subjects with no history of knee pathology, both knees were tested. In group 2, which consisted of nine patients with unilateral PFP, only the painful knee was tested. In group 3, which consisted of the same nine patients who comprised group 2, only the nonpainful knee was tested. Nonnormalized and normalized VMO:VL IEMG ratios were computed for ascending stairs, descending stairs, submaximal isometric contraction, and maximal isometric contraction (nonnormalized only). A two-way analysis of variance for repeated measures indicated VMO:VL ratios for isotonic stair-climbing activities were significantly greater than VMO:VL ratios for isometric contractions. Nonnormalized VMO:VL ratios in group 1 were significantly greater than nonnormalized VMO:VL ratios in the other two groups. Patients with PFP may have abnormal VMO:VL activation patterns, and isotonic quadriceps femoris muscle exercise may elicit more favorable muscle activation patterns than isometric exercise for patients with PFP.

Exercise programs for patients with post-polio syndrome: a case report.

Several authors have reported on post-polio syndrome, indicating a decline in muscle strength in individuals years after the onset of poliomyelitis. These reports include suggestions that strenuous exercise programs are contraindicated and may have deleterious effects for patients with post-polio syndrome. The purpose of this case study was to examine the effects of an aggressive, six-week isokinetic exercise program on a 59-year-old patient with post-polio syndrome. Peak torque values were assessed before and during the exercise program, and 6 and 22 weeks following cessation of the exercise program. The results indicate no deleterious effects secondary to the exercise program. The authors suggest future research strategies to investigate the efficacy of exercise programs for patients with post-polio syndrome.

Effect of including a clinical example on the ability of physical therapists to apply information in a technical research report.

BACKGROUND AND PURPOSE: The purpose of this study was to determine whether an example in a technical research report would affect application of content to hypothetical patient problems and to future patients. SUBJECTS: Subjects were 69 physical therapists who routinely used isokinetic equipment in the treatment of patients with knee joint pathologies. METHODS: Thirty-five subjects (group 1) read a research report that described mathematical models for predicting preinjury quadriceps femoris and hamstring muscle performance. The report included an example of applying the information. The remaining 34 subjects (group 2) read the same research report with the example omitted. Subjects were asked to select appropriate prediction models and determine preinjury knee torques for two hypothetical patients. Subjects were also contacted 6 to 12 weeks after initial data collection to determine whether they had applied research report results in their treatments of patients. RESULTS: Chi-square analyses indicated manuscript type was not related to the selection of correct models, but group 1 subjects computed correct torque values more frequently than did group 2 subjects. Insufficient data were available regarding application of research report content to patients. CONCLUSION AND DISCUSSION: The results indicate application of technically oriented research reports may be enhanced by including examples of applications. (Gross MT, Sekerak DK, Allen DD. Effect of including a clinical example on the ability of physical therapists to apply information in a technical research report.

Relationship between multiple predictor variables and normal knee torque production.

The purpose of this study was to develop predictive models relating isokinetic knee testing performance to anthropometric and demographic variables. The subjects were 134 healthy volunteers (70 female, 64 male) between the ages of 10 and 80 years. The investigators measured subjects' peak knee flexion and extension torque production at two angular velocities. Stepwise regression analyses were used to examine the relationship between each torque-dependent variable and the following potential predictor variables: age, sex, side of lower extremity dominance, height, weight, percentage of body fat, and thigh girth. The investigators generated two sets of models designed to predict preinjury knee strength. Clinicians can use one set of models by assessing predictor variables before or immediately following injury. The second set of models involves the assessment of predictor variables postinjury, excluding an assessment of percentage of body fat and thigh girth. The results indicated that peak knee torque production can be predicted with statistically significant accuracy (multiple R = .78-.87). The predictive models generated in this study can be used to establish muscle strength goals for patient rehabilitative programs.

Simultaneous palpation of the craniosacral rate at the head and feet: intrarater and interrater reliability and rate comparisons.

BACKGROUND AND PURPOSE: The main purpose of this study was to determine the interrater and intrarater reliability of measurements obtained during palpation of the craniosacral rate at the head and feet. Palpated craniosacral rates of head and feet measured simultaneously were also compared. Subjects. Twenty-eight adult subjects and 2 craniosacral examiners participated in the study. METHODS: A within-subjects repeated-measures design was used. A standard cubicle privacy curtain, hung over the subject's waist, was used to prevent the examiners from seeing each other. RESULTS: Interrater intraclass correlation coefficients (ICCs) were .08 at the head and .19 at the feet. Intrarater ICCs ranged from .18 to .30. Craniosacral rates simultaneously palpated at the head and feet were different. CONCLUSION AND DISCUSSION: The results did not support the theories that underlie craniosacral therapy or claims that craniosacral motion can be palpated reliably.

Validity of knee flexion and extension peak torque prediction models.

The primary purpose of this study was to test the validity of predictive models relating isokinetic knee torque production to anthropometric and demographic variables. Subjects were 23 healthy female and 15 healthy male volunteers between the ages of 10 and 77 years. We measured subjects' peak knee flexion and extension torque production at two angular velocities. For each torque dependent variable, we calculated a Pearson product-moment correlation coefficient between the measured torque values and the values obtained with prediction equations. The difference between the squared value of the correlation coefficients and the regression multiple R2 values obtained for an original group of 134 subjects ranged between .05 and .10 for the torque dependent variables. The results indicate the validity of the regression models at the level specified by the multiple regression R2 values. Clinicians can use the prediction equations presented in this article to establish rehabilitation goals for patients and can estimate the error involved in applying each prediction equation.

Lower quarter screening for skeletal malalignment--suggestions for orthotics and shoewear.

Skeletal malalignments of the lower quarter, deformities within a bone or at a joint, may be the primary cause of musculoskeletal patient problems. Skeletal malalignments also may sustain the presence of a musculoskeletal patient problem that has some other causal mechanism. A screening exam for skeletal alignment of the lower quarter may assist clinicians in identifying skeletal malalignments that are associated with a musculoskeletal complaint. The purposes of this paper are to: 1) describe components for a skeletal alignment screening exam, 2) analyze how lower quarter malalignments may influence lower quarter function and contribute to the development of musculoskeletal pathology, and 3) suggest general characteristics of foot orthoses and shoes that may assist in the management of musculoskeletal patient problems of the lower quarter.

Chronic tendinitis: pathomechanics of injury, factors affecting the healing response, and treatment.

This paper is adapted from: Gross MT: Tendinitis. In: Prentice W, Hooker DN (eds), Postgraduate Advances in Sports Physical Therapy, I-III, pp 1-14. Berryville, VA: Forum Medicum, Inc., 1990. Figures and segments of text in this paper are reprinted with permission of Forum Medicum, Inc. Chronic tendinitis is a common and debilitating musculoskeletal pathology that can be particularly recalcitrant to treatment. Details of the composition and structure of tendon are presented, enabling clinicians to understand the mechanical function of tendon under different loading conditions and the various mechanisms of tendinitis injury. The effects of exercise, disuse, the incidence of injury, and tendinitis terminology are discussed. Other purposes of this paper are to describe the natural course of tendon healing, the clinical assessment of tendinitis, and suggested treatments for chronic tendinitis. The paper concludes with two case studies. Information in this paper should assist the clinician in treating chronic tendinitis more successfully. J Orthop Sports Phys Ther 1992;16(6):248-261.

Effect of foot position on electromyographic activity of the vastus medialis oblique and vastus lateralis during lower-extremity weight-bearing activities.

STUDY DESIGN: Repeated measures analysis of the effects of foot wedges on quadriceps muscle function. OBJECTIVES: To investigate the relationship between foot position and 2 quadriceps muscle activation conditions: maximum voluntary isometric quadriceps muscle contractions with the knee extended and 1-leg short squats with a knee flexion range of motion of 0 degree to 50 degrees. BACKGROUND: Abnormal foot position has been suggested as an important factor which may lead to patellofemoral malalignment. No previous studies have examined the effects of foot position on activation of the vastus medialis oblique (VMO) and vastus lateralis (VL) muscles using weight-bearing exercises. METHODS AND MEASURES: Sixteen healthy volunteers performed the 2 exercises under 3 foot conditions: level surface, a 10 degrees medial wedge, and a 10 degrees lateral wedge. Subjects' electromyographic data for the VMO and VL were analyzed using ANOVA. RESULTS: The normalized VMO/VL ratio was significantly greater during the short squat than during the maximum voluntary isometric muscle contractions, but no significant differences were identified across the 3 foot positions. CONCLUSIONS: Clinicians should understand that the benefit of using a foot orthotic to correct a pronated or supinated foot might not result from a change in quadriceps muscle activation intensity but from other mechanical factors.

Intraexaminer reliability, interexaminer reliability, and mean values for nine lower extremity skeletal measures in healthy naval midshipmen.

Physical therapists, athletic trainers, and other health care professionals commonly evaluate static postures and dynamic motions in patients with skeletal malalignments of the lower extremity. Accurate clinical evaluation of these malalignments depends on reliable and valid measures as well as established normal values. The purpose of this study was to document the intraexaminer and interexaminer reliability and mean values for nine static lower extremity skeletal measures in healthy Naval midshipmen. The measures studied were femoral torsion, ankle dorsiflexion, tibial length, leg length discrepancy, genu varus/valgus, medial talonavicular joint bulge, rearfoot angle, arch angle, and foot type classification. Intraexaminer and interexaminer reliability ICCs ranged between .65 and .97, and percentage agreements ranged between 88.8 and 94.4%. Mean absolute difference values all were within acceptable limits for clinical measurement. A foot type classification scheme was suggested. The results of this study indicate that the measures investigated are reliable when conducted on healthy Naval midshipmen by experienced examiners. Suggestions for further research are offered.

An electromyographical analysis of the scapular stabilizing synergists during a push-up progression.

Current literature recommends incorporating push-up progressions into upper extremity rehabilitation for advanced training of the scapular stabilizers. No documentation exists to demonstrate changes in the level of muscle activation when push-up progressions are performed. The purpose of this study was to determine the effect of difficulty level for push-ups on electrical activity of the scapular stabilizing synergists. Sixteen subjects performed five repetitions for each of the three conditions in a push-up progression. Electromyographic data collected on the serratus anterior, upper trapezius, and lower trapezius revealed a statistically significant interaction effect between the serratus anterior and upper trapezius and push-up condition when the feet were elevated. No significant interaction was found between push-up condition and the lower trapezius. This study supports the clinical use of push-up progressions to facilitate activation of the serratus anterior and the upper trapezius during upper extremity rehabilitation.

Comparison of Johnson Anti-Shear Accessory and Standard Dynamometer Attachment for Anterior and Posterior Tibial Translation during Isometric Muscle Contractions.

The purpose of this study was to compare the effectiveness of the Johnson Anti-Shear Accessory (JASA) and the standard dynamometer accessory (SDA) in controlling tibial translation for isometric knee flexion and extension exercise on the Cybex(R) II. The subject was a 26-year-old male with known anterior cruciate ligament (ACL) deficiency of the left knee. The subject performed maximum isometric muscle contractions for JASA and SDA conditions. Medial-lateral roentgenograms were obtained while the subject maintained isometric knee flexion and extension muscle contractions at three positions of knee flexion. JASA and SDA trials were analyzed for one extension position and one flexion position. The authors compared JASA and SDA conditions for magnitude of contact pad force and for degree of tibial translation evidenced on the roentgenograms. Tibial translation was greater and contact pad force was less for the SDA condition than the JASA condition. The results suggest the JASA is useful in protecting ACL surgical reconstructions, the partially torn ACL, and secondary supporting structures of the knee as patients perform isometric exercise on Cybex instrumentation. J Orthop Sports Phys Ther 1990;11(11):547-553.

Relationship between Multiple Predictor Variables and Normal Biodex Eversion-Inversion Peak Torque and Angular Work.

Normative data should help in the development of treatment goals. The purpose of this study was to generate predictive models relating isokinetic ankle testing performance to anthropometric and demographic variables. The subjects were 44 healthy females (age = 40.48, s = 11.98) and 43 healthy males (age = 39.83, s = 10.31) between the ages of 19 and 62. For each subject the investigators measured concentric peak torque and angular work at 60 and 120 degrees /sec for Biodex eversion and inversion. Stepwise regression analyses were used to examine the relationship between each isokinetic variable and the following predictor variables: age, side of lower extremity dominance, height, weight, percentage of body fat, leg girth, and shoe size. Separate analyses were conducted for females and males. The results indicate a significant relationship (p < 0.001) between multiple variable models and the isokinetic performance variables. The magnitude of the relationships may be explained, in part, by the restricted range of Biodex eversion and inversion measurements of peak torque and angular work. The models generated in this study can be used to establish muscle performance goals for patient rehabilitation programs. J Orthop Sports Phys Ther 1992;15(1):24-31.

Effect of foot orthotics on calcaneal eversion during standing and treadmill walking for subjects with abnormal pronation.

STUDY DESIGN: Repeated measures analysis of intervention. OBJECTIVES: To determine the effects of foot orthotics and shoewear on calcaneal eversion for standing and treadmill walking. BACKGROUND: Foot orthotics are commonly used as an intervention for treating lower extremity musculoskeletal pathology. Qualitative research regarding the benefit of foot orthotics tends to be favorable, while the results of quantitative studies often conflict. METHODS AND MEASURES: Eight men (mean age = 35.8 +/- 12.7 years) and 5 women (mean age = 30.4 +/- 10.6 years), who demonstrated abnormal pronation, walked quickly (average velocity = 1.9 m/s) on a treadmill with and without foot orthotics. Subjects were filmed using a 2-dimensional video system and plastic molds designed to indicate calcaneal position inside the shoe during static standing and treadmill walking. RESULTS: Paired t tests indicated that foot orthotics significantly reduced the mean maximum calcaneal eversion angle by 2.2 degrees and the mean calcaneal eversion angle at heel rise by 2.1 degrees during fast walking. Orthotic and nonorthotic conditions did not differ significantly for the remaining kinematic variables. A one-way ANOVA indicated that calcaneal eversion in standing was significantly greater for barefoot standing compared with standing in shoes with or without orthotics. ANOVA also indicated that the plastic molds provided reliable measures of calcaneal position. CONCLUSIONS: Foot orthotics have a significant effect on calcaneal eversion and shoes also should be considered in conjunction with foot orthotic prescription.

A comparison of trunk extensor strength and squat lifting ability.

Back testing devices are frequently utilized in the clinic to assess function and return to work readiness in place of the job task, yet little research on their validity has been reported. This study was conducted to determine if correlations exist between squat lifting and isoinertial and isometric trunk extensor strength, torso length and isoinertial and isometric trunk extensor strength, and body weight and isoinertial and isometric trunk extensor strength. Twenty-eight subjects participated in two sessions involving B200 testing and 30.5 cm to knuckle lifting ability. Regression and correlations were performed. The results indicate that body weight and torso length do not demonstrate a relationship with trunk extensor strength, and isometric and isoinertial trunk extensor strength cannot be used accurately to estimate one's 30.5 cm to knuckle lifting ability. In conclusion, other anthropometric measures should be investigated if anthropometrics are used to estimate strength, and functional testing should be used to evaluate function.

Effect of knee angle and ligament insufficiency on anterior tibial translation during quadriceps muscle contraction: a preliminary report.

Additional information is needed regarding the effects of exercise protocols on the injured or reconstructed anterior cruciate ligament (ACL). The purpose of this investigation was to assess the effects of knee flexion angle and ACL insufficiency on anterior tibial translation (ATT) and patellar ligament insertion angle as subjects performed maximal isometric quadriceps muscle contractions. The subjects were two females and two males between the ages of 18 and 24 who had sustained injuries that resulted in unilateral ACL insufficiency. Each subject performed maximum isometric quadriceps muscle contractions with each leg on a Cybex II dynamometer at each of three positions: 15, 45, and 75 degrees knee flexion. A lateral knee roentgenogram was obtained as each subject maintained each isometric muscle contraction. A roentgenogram also was taken as subjects rested each knee in each of the three target positions. Anterior tibial translation for each isometric muscle contraction was assessed by measuring the anterior displacement of the tibial plateau on the isometric resisted roentgenogram relative to the resting roentgenogram. Patellar ligament insertion angle also was measured for each roentgenogram. Maximum ATT occurred at the 15 degrees knee flexion target angle for two subjects and at the 45 degrees target angle for the other two subjects. Patellar ligament insertion angle decreased as knee flexion angle increased. Appreciable stress may be imposed on the ACL as patients perform maximum quadriceps muscle contractions in positions of terminal knee extension and in midrange positions previously reported as being safe for maximal effort quadriceps exercise. Magnitude of stress imposed on the ACL is discussed as a function of the length-tension relationship of the quadriceps muscle-tendon unit and insertion angle of the patellar ligament. Suggestions are made for additional research regarding appropriate muscle strengthening protocols for patients who have undergone ACL reconstruction.

Comparison of ball-and-racquet impact force between two tennis backhand stroke techniqes.

STUDY DESIGN: A mixed design for kinetic comparison of 2 types of one-handed backhand strokes and 2 skill levels in tennis. OBJECTIVES: To develop and evaluate a model to estimate the impact force on the racquet during tennis stroke, and to compare the peak impact force between one-handed backhand stroke with a long backswing and one-handed backhand stroke with a short backswing and between the beginning and advanced players. BACKGROUND: A one-handed backhand stroke is commonly used in tennis and may be associated with many upper extremity over-use injuries. An understanding of kinetics of the backhand stroke is essential for understanding injury mechanisms and prevention. METHODS AND MEASURES: Five male advanced tennis players and 4 male and 1 female beginning tennis players participated. Mean age was 32.2 +/- 7.0 years. Each subject was instructed to use the 2 types of one-handed backhand strokes to hit balls from a tennis ball machine. Three-dimensional coordinates of critical body and racquet landmarks were obtained. A mathematical model was developed to estimate the contact duration and the peak impact force during a stroke. RESULTS: The estimated peak impact forces were reproducible and comparable to those reported in the literature from direct measurements. A one-handed backhand stroke with a short backswing had a significantly shorter contact duration (0.008 +/- 0.003 seconds) and a greater peak resultant impact force (330.0 +/- 140.7) than that with a long backswing (0.016 +/- 0.004 seconds and 180.8 +/- 49.1 N). Skill level did not significantly affect the peak resultant impact force. CONCLUSION: A long backswing in a one-handed backhand stroke may reduce the load on the upper extremity and may assist in reducing the risks of tennis-related upper extremity over-use injuries.