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1.  A counterbalanced cross-over study of the effects of visual, auditory and no feedback on performance measures in a simulated cardiopulmonary resuscitation 
BMC Nursing  2011;10:15.
Previous research has demonstrated that trained rescuers have difficulties achieving and maintaining the correct depth and rate of chest compressions during both in and out of hospital cardiopulmonary resuscitation (CPR). Feedback on rate and depth mitigate decline in performance quality but not completely with the residual performance decline attributed to rescuer fatigue. The purpose of this study was to examine the effects of feedback (none, auditory only and visual only) on the quality of CPR and rescuer fatigue.
Fifteen female volunteers performed 10 minutes of 30:2 CPR in each of three feedback conditions: none, auditory only, and visual only. Visual feedback was displayed continuously in graphic form. Auditory feedback was error correcting and provided by a voice assisted CPR manikin. CPR quality measures were collected using SkillReporter® software. Blood lactate (mmol/dl) and perceived exertion served as indices of fatigue. One-way and two way repeated measures analyses of variance were used with alpha set a priori at 0.05.
Visual feedback yielded a greater percentage of correct compressions (78.1 ± 8.2%) than did auditory (65.4 ± 7.6%) or no feedback (44.5 ± 8.1%). Compression rate with auditory feedback (87.9 ± 0.5 compressions per minute) was less than it was with both visual and no feedback (p < 0.05). CPR performed with no feedback (39.2 ± 0.5 mm) yielded a shallower average depth of compression and a lower percentage (55 ± 8.9%) of compressions within the accepted 38-50 mm range than did auditory or visual feedback (p < 0.05). The duty cycle for auditory feedback (39.4 ± 1.6%) was less than it was with no feedback (p < 0.05). Auditory feedback produced lower lactate concentrations than did visual feedback (p < 0.05) but there were no differences in perceived exertion.
In this study feedback mitigated the negative effects of fatigue on CPR performance and visual feedback yielded better CPR performance than did no feedback or auditory feedback. The perfect confounding of sensory modality and periodicity of feedback (visual feedback provided continuously and auditory feedback provided to correct error) leaves unanswered the question of optimal form and timing of feedback.
PMCID: PMC3162914  PMID: 21810239
2.  Pulsed Shortwave Diathermy and Prolonged Long-Duration Stretching Increase Dorsiflexion Range of Motion More Than Identical Stretching Without Diathermy 
Journal of Athletic Training  2002;37(1):43-50.
Objective: To compare the effects of 3 treatments on ankle dorsiflexion range of motion: prolonged long-duration stretching, pulsed shortwave diathermy followed by stretching, and pulsed shortwave diathermy, stretching, and ice combined.
Design and Setting: A 2 × 5 × 15 repeated-measures (on 2 factors) design guided this study. Range-of-motion change in triceps surae flexibility was the dependent variable. The 3 independent variables were treatment group, pretest and posttest measurements, and day. Treatment group had 4 levels: control, stretching (10 minutes of stretching via the weight and pulley), diathermy and stretching (20 minutes of diathermy and 10 minutes of stretching), and diathermy, stretching, and ice (20 minutes of diathermy, 10 minutes of stretching applied after 15 minutes of diathermy, and 5 minutes of ice applied during the last 5 minutes of stretching). Each subject received 14 treatments throughout 3 weeks, with a follow-up measurement taken 6 days after the last treatment.
Subjects: Forty-four healthy college-student volunteers not involved in any flexibility program.
Measurements: We measured ankle dorsiflexion using a digital inclinometer before and after treatment.
Results: After 14 days of treatment, the range-of-motion increase was greater after heat and stretching than after stretching alone. After 6 additional days of rest, the heat and stretching range-of-motion increase was greater than that for stretching alone.
Conclusion: Pulsed shortwave diathermy application before prolonged long-duration static stretching was more effective than stretching alone in increasing flexibility throughout 3 weeks. After 14 treatments, prolonged long-duration stretching combined with pulsed shortwave diathermy followed by ice application caused greater immediate and net range-of-motion increases than prolonged long-duration stretching alone.
PMCID: PMC164307  PMID: 12937443
ice; deep heating; flexibility
3.  The Carry-Over Effects of Diathermy and Stretching in Developing Hamstring Flexibility 
Journal of Athletic Training  2002;37(1):37-42.
Objective: To compare the effects of low-load, short-duration stretching with or without high-intensity, pulsed short-wave diathermy on hamstring flexibility.
Design and Setting: We used a single-blind, repeated-measures design (pretest and posttest for all treatments) that included a placebo. The 3 independent variables were treatment mode, pretest and posttest measurements, and day. Treatment mode had 3 levels: diathermy and stretching, stretching alone, and control. The dependent variable was range of motion. Subjects were randomly assigned to the diathermy and stretching, stretching-only, or control group. Subjects were treated and tested each day (at approximately the same time) for 5 days, with a follow-up test administered 72 hours later. Hamstring flexibility was tested using a sit-and-reach box before and after each treatment. Diathermy and stretching subjects received a 15-minute diathermy treatment on the right hamstring at a setting of 7000 pulses per second, with an average pulse width of 95 μsec. Stretching-only subjects received a 15-minute sham diathermy treatment. Both diathermy and stretching and stretching-only subjects then performed three 30-second stretches (short duration) before being retested. Control subjects lay prone for 15 minutes before being retested.
Subjects: Thirty-seven healthy college students (11 men, 26 women, age = 20.46 ± 1.74 years) volunteered.
Measurements: Hamstring flexibility was measured using a sit-and-reach box before and after each treatment.
Results: The average increases in hamstring flexibility over the 5 treatment days for the diathermy and stretching, stretching-only, and control groups were 6.06 cm (19.6%), 5.27 cm (19.7%), and 3.38 cm (10.4%), respectively. Three days later (after no treatment), the values for the diathermy and stretching, stretching-only, and control groups were 8.27 cm (26.7%), 6.83 cm (25.3%), and 4.15 cm (14.2%), respectively. No significant differences in hamstring flexibility were noted among the groups.
Conclusions: Diathermy and short-duration stretching were no more effective than short-duration stretching alone at increasing hamstring flexibility. The effects of diathermy with longer stretching times need to be researched.
PMCID: PMC164306  PMID: 12937442
heat; stretch; injury treatment
4.  Effects of High-Top and Low-Top Shoes on Ankle Inversion 
Journal of Athletic Training  2000;35(1):38-43.
To determine the differences in the rate and amount of ankle inversion in subjects wearing high-top and low-top shoes.
Design and Setting:
Subjects were filmed at 60 Hz while on an inversion platform that suddenly inverted the right ankle 35°. We measured 5 trials of sudden inversion for each subject in high-top and low-top shoes.
Twenty male subjects with no history of lower leg injury within the previous 6 months.
We measured ankle inversion using video motion analysis techniques at 60 Hz. A2 x 5 factorial repeated- measures analysis of variance was used to test for significant differences in the amount of inversion, average rate of inversion, and maximum rate of inversion.
The high-top shoes significantly reduced the amount and rate of inversion. The high-top shoes reduced the amount of inversion by 4.5°, the maximum rate of inversion by 100.1°/s, and the average rate of inversion by 73.0°/s.
The high-top shoes were more effective in reducing the amount and rate of inversion than the low-top shoes. Depending upon the loading conditions, high-top shoes may help prevent some ankle sprains.
PMCID: PMC1323436  PMID: 16558606
shoe design; inversion; ankle injury; ligament
5.  The Effects of Spatting and Ankle Taping on Inversion Before and After Exercise 
Journal of Athletic Training  1997;32(1):29-33.
To compare the effects of spatting, taping and spatting, taping, and not taping on the amount and rate of inversion of the ankle before and after exercise.
Design and Setting:
We filmed subjects at 60 Hz while they stood on a platform that suddenly inverted the right ankle. Five trials were measured before and after a 30-minute period of drills.
We tested 15 male rugby players with no history of lower-leg injury within the previous 6 months limiting activity for more than 2 days.
The amount and rate of inversion in the four conditions were digitized and analyzed.
The combination of spatting and taping was the most effective in reducing inversion rate and range of motion before and after exercise.
All three taping treatments were effective in reducing the amount and rate of inversion. Exercise loosened the tape, but there may be a functional restriction of the amount and rate of inversion after exercise.
PMCID: PMC1319232  PMID: 16558429
spatting; ankle taping; taping; sprain; inversion; ankle injury; video analysis; external supports
6.  The Effects of High-Volt Pulsed Current Electrical Stimulation on Delayed-Onset Muscle Soreness 
Journal of Athletic Training  1997;32(1):15-20.
We investigated three 30-minute high-volt pulsed current electrical stimulation (HVPC) treatments of 125 pps to reduce pain, restore range of motion (ROM), and recover strength loss associated with delayed-onset muscle soreness (DOMS).
Design and Setting:
Randomized, masked comparison of three 30-minute treatment and sham HVPC regimens over a 48-hour period.
Twenty-eight college students.
Subjects performed concentric and eccentric knee extensions with the right leg to induce muscle soreness. Assessments were made before and after the exercise bout and each treatment at 24, 48, and 72 hours postexercise.
Three separate 2 × 3 × 2 ANOVAs were used to determine significant differences (p < .05) between days, treatments, and pre-post treatment effects and significant interaction among these variables. Scheffe post hoc tests showed no significant reduction in pain perception or improvement in loss of function at 24, 48, and 72 hours postexercise. Mean pain perception assessments (0 = no pain, 10 = severe pain) for the HVPC group were 2.9, 4.5, and 3.5 and for the sham group 3.8, 4.8, and 3.5). Mean ROM losses for the HVPC group were 9.0°, 22.3°, and 26.2°, and for the sham group were 9.5°, 23.1°, and 23.0°. Mean strength losses (1RM) for the HVPC group were 25.9, 25.7, and 20.8 lbs and for the sham group were 22.3, 22.3, and 13.8 lbs.
HVPC as we studied it was ineffective in providing lasting pain reduction and at reducing ROM and strength losses associated with DOMS.
PMCID: PMC1319229  PMID: 16558426
muscle soreness; delayed-onset muscle soreness (DOMS);; high-volt pulsed current
7.  Rate of Temperature Decay in Human Muscle Following 3 MHz Ultrasound: The Stretching Window Revealed 
Journal of Athletic Training  1995;30(4):304-307.
Researchers have determined that when therapeutic ultrasound vigorously heats connective tissue, it can be effective in increasing extensibility of collagen affected by scar tissue. These findings give credence to the use of continuous thermal ultrasound to heat tissue before stretching, exercise, or friction massage in an effort to decrease joint contractures and increase range of motion. Before our investigation, it was not known how long following an ultrasound treatment the tissue will remain at a vigorous heating level (>3°C). We conducted this study to determine the rate of temperature decay following 3 MHz ultrasound, in order to determine the time period of optimal stretching. Twenty subjects had a 23-gauge hypodermic needle microprobe inserted 1.2 cm deep into the medial aspect of their anesthetized triceps surae muscle. Subjects then received a 3 MHz ultrasound treatment at 1.5 W/cm2 until the tissue temperature was increased at least 5°C. The mean baseline temperature before each treatment was 33.8 ± 1.3°C, and it peaked at 39.1 ± 1.2°C from the ultrasound. Immediately following the treatment, we recorded the rate at which the temperature dropped at 30-second intervals. We ran a stepwise nonlinear regression analysis to predict temperature decay as a function of time following ultrasound treatment. We found a significant nonlinear relationship between time and temperature decay. The average time it took for the temperature to drop each degree as expressed in minutes and seconds was: 1°C = 1:20; 2°C = 3:22; 3°C = 5:50; 4°C = 9:13; 5°C = 14:55; 5.3°C = 18:00 (baseline). We conclude that under similar circumstances where the tissue temperature is raised 5°C, stretching will be effective, on average, for 3.3 minutes following an ultrasound treatment. To increase this stretching window, we suggest that stretching be applied during and immediately after ultrasound application.
PMCID: PMC1317998  PMID: 16558352
8.  A randomized cross-over study of the quality of cardiopulmonary resuscitation among females performing 30:2 and hands-only cardiopulmonary resuscitation 
BMC Nursing  2009;8:6.
Hands-Only cardiopulmonary resuscitation (CPR) is recommended for use on adult victims of witnessed out-of-hospital (OOH) sudden cardiac arrest or in instances where rescuers cannot perform ventilations while maintaining minimally interrupted quality compressions. Promotion of Hands-Only CPR should improve the incidence of bystander CPR and, subsequently, survival from OOH cardiac arrest; but, little is known about a rescuer's ability to deliver continuous chest compressions of adequate rate and depth for periods typical of emergency services response time. This study evaluated chest compression rate and depth as subjects performed Hands-Only CPR for 10 minutes. For comparison purposes, each also performed chest compressions with ventilations (30:2) CPR. It also evaluated fatigue and changes in body biomechanics associated with each type of CPR.
Twenty healthy female volunteers certified in basic life support performed Hands-Only CPR and 30:2 CPR on a manikin. A mixed model repeated measures cross-over design evaluated chest compression rate and depth, changes in fatigue (chest compression force, perceived exertion, and blood lactate level), and changes in electromyography and joint kinetics and kinematics.
All subjects completed 10 minutes of 30:2 CPR; but, only 17 completed 10 minutes of Hands-Only CPR. Rate, average depth, percentage at least 38 millimeters deep, and force of compressions were significantly lower in Hands-Only CPR than in 30:2 CPR. Rates were maintained; but, compression depth and force declined significantly from beginning to end CPR with most decrement occurring in the first two minutes. Perceived effort and joint torque changes were significantly greater in Hands-Only CPR. Performance was not influenced by age.
Hands-Only CPR required greater effort and was harder to sustain than 30:2 CPR. It is not known whether the observed greater decrement in chest compression depth associated with Hands-Only CPR would offset the potential physiological benefit of having fewer interruptions in compressions during an actual resuscitation. The dramatic decrease in compression depth in the first two minutes reinforces current recommendations that rescuers take turns performing compressions, switching every two minutes or less. Further study is recommended to determine the impact of real-time feedback and dispatcher coaching on rescuer performance.
PMCID: PMC2715393  PMID: 19583851
9.  The Effects of a 6-Week Plyometric Training Program on Agility 
The purpose of the study was to determine if six weeks of plyometric training can improve an athlete's agility. Subjects were divided into two groups, a plyometric training and a control group. The plyometric training group performed in a six week plyometric training program and the control group did not perform any plyometric training techniques. All subjects participated in two agility tests: T-test and Illinois Agility Test, and a force plate test for ground reaction times both pre and post testing. Univariate ANCOVAs were conducted to analyze the change scores (post - pre) in the independent variables by group (training or control) with pre scores as covariates. The Univariate ANCOVA revealed a significant group effect F2,26 = 25.42, p=0.0000 for the T-test agility measure. For the Illinois Agility test, a significant group effect F2,26 = 27.24, p = 0.000 was also found. The plyometric training group had quicker posttest times compared to the control group for the agility tests. A significant group effect F2,26 = 7.81, p = 0.002 was found for the Force Plate test. The plyometric training group reduced time on the ground on the posttest compared to the control group. The results of this study show that plyometric training can be an effective training technique to improve an athlete's agility.
Key PointsPlyometric training can enhance agility of athletes.6 weeks of plyometric training is sufficient to see agility results.Ground reaction times are decreased with plyometric training
PMCID: PMC3842147  PMID: 24353464
Jumping; training; performance variables; quickness
10.  The Effects of Bicycle Frame Geometry on Muscle Activation and Power During a Wingate Anaerobic Test 
The purpose of this study was to compare the effects of bicycle seat tube angles (STA) of (72° and 82°) on power production and EMG of the vastus laeralis (VL), vastus medialis (VM), semimembranous (SM), biceps femoris (BF) during a Wingate test (WAT). Twelve experienced cyclists performed a WAT at each STA. Repeated measures ANOVA was used to identify differences in muscular activation by STA. EMG variables were normalized to isometric maximum voluntary contraction (MVC). Paired t-tests were used to test the effects of STA on: peak power, average power, minimum power and percent power drop. Results indicated BF activation was significantly lower at STA 82° (482.9 ± 166.6 %MVC·s) compared to STA 72° (712.6 ± 265.6 %MVC·s). There were no differences in the power variables between STAs. The primary finding was that increasing the STA from 72° to 82° enabled triathletes’ to maintain power production, while significantly reducing the muscular activation of the biceps femoris muscle.
Key PointsRoad cyclists claim that bicycle seat tube angles between 72° and 76° are most effective for optimal performance in racing.Triathletes typically use seat tube angles greater than 76°. It is thought that a seat tube angle greater than 76° facilitates a smoother bike to run transition in the triathlon.Increasing the seat tube angle from 72 to 82 enabled triathletes’ to maintain power production, while significantly reducing the muscular activation of the biceps femoris muscle.Reduced hamstring muscular activation in the triathlon frame (82 seat tube angle) may serve to reduce hamstring tightness following the bike phase of the triathlon, allowing the runner to use a longer stride length.
PMCID: PMC3818671  PMID: 24198678
Cycling; anaerobic power; triathlon; efficiency; EMG
11.  Effects of Tape and Exercise on Dynamic Ankle Inversion 
Journal of Athletic Training  2000;35(1):31-37.
To compare the effects of tape, with and without prewrap, on dynamic ankle inversion before and after exercise.
Design and Setting:
Doubly multivariate analyses of variance were used to compare the taping and exercise conditions. Subjects were randomly assigned to a fixed treatment order as determined by a balanced latin square. The independent variables were tape application (no tape, tape with prewrap, tape to skin) and exercise (before and after). The dependent variables were average inversion velocity, total inversion, maximum inversion velocity, and time to maximum inversion.
Thirty college-age male and female students (17 males, 13 females; mean age = 24.9 ± 4.3 years, range, 19 to 39 years) were tested. Subjects were excluded from the study if they exhibited a painful gait or painful range of motion or had a past history of ankle surgery or an ankle sprain within the past 4 weeks.
We collected data using electronic goniometers while subjects balanced on the right leg on an inversion platform tilted about the medial-lateral axis to produce 15° of plantar flexion. Sudden ankle inversion was induced by pulling the inversion platform support, allowing the platform support base to rotate 37°. Ten satisfactory trials were recorded on the inversion platform before and after a prescribed exercise bout. We calculated total inversion, time to maximum inversion, average inversion velocity, and maximum inversion velocity after sudden inversion.
We found no significant differences between taping to the skin and taping over prewrap for any of the variables measured. There were significant differences between both taping conditions and no-tape postexercise for average inversion velocity, maximum inversion, maximum inversion velocity, and time to maximum inversion. The total inversion mean for no-tape postexercise was 38.8° ± 6.3°, whereas the means for tape and skin and for tape and prewrap were 28.3° ± 4.6° and 29.1° ± 4.7°, respectively. After exercise, inversion increased by 1.0° ± 2.8° for the no-tape condition, whereas the tape-to-skin and tape-over-prewrap inversion increased by 2.1° ± 3.2° and 1.7° ± 2.2°, respectively.
There was no difference in the amount of inversion restriction when taping with prewrap was compared with taping to the skin. Tape and tape with prewrap significantly reduced the average inversion velocity, maximum inversion, maximum inversion velocity, and the time to maximum inversion. Both taping conditions offered residual restriction after exercise.
PMCID: PMC1323435  PMID: 16558605
ankle taping; prewrap; inversion; ankle sprain; inversion platform
12.  An Electromyographic Investigation of 4 Elastic-Tubing Closed Kinetic Chain Exercises After Anterior Cruciate Ligament Reconstruction 
Journal of Athletic Training  1998;33(4):328-335.
To determine the electromyographic (EMG) activity of the vastus medialis oblique (VMO), vastus lateralis (VL), semitendinosus and semimembranosus (ST), and biceps femoris (BF) muscles during 4 elastic-tubing closed kinetic chain exercises in postoperative patients with anterior cruciate ligament (ACL)-reconstructed knees.
Design and Setting:
A 4 × 4 repeated-measures analysis of variance design guided this study. Independent variables were type of exercise and muscle; the dependent variable was EMG activity.
Fifteen patients, 5 to 24 weeks after ACL reconstruction.
Subjects performed 4 exercises (front pull, back pull, crossover, reverse crossover) with elastic tubing attached to the foot of the uninjured leg. Time-and amplitude- normalized EMG activity was recorded from the VMO, VL, ST, and BF muscles of the injured leg. The hamstrings: quadriceps ratio was calculated.
The normalized VMO, VL, and BF EMG activity ranged from 25% to 50% of maximum voluntary isometric contraction for the 4 exercises. The ST ranged from 12% on the back pull to 58% on the front pull. The hamstrings: quadriceps ratios were 137% (front pull), 115% (crossover), 70% (back pull), and 60% (reverse crossover).
We suggest that clinicians use these exercises during early ACL rehabilitation since they incorporate early weightbearing with hamstring and quadriceps coactivation.
PMCID: PMC1320583  PMID: 16558530
EMG; ACL rehabilitation; knee rehabilitation
13.  Immediate and Residual Changes in Dorsiflexion Range of Motion Using an Ultrasound Heat and Stretch Routine 
Journal of Athletic Training  1998;33(2):141-144.
With respect to increasing ankle dorsiflexion range of motion, our objective was to examine the influence, if any, of preheating the triceps surae with ultrasound before stretching.
Design and Setting:
Subjects were assigned to either group A (ultrasound and stretch) or group B (stretch alone). Group A received 3-MHz ultrasound (1.5 W/cm2, 4 times effective radiating area) for 7 minutes to the musculotendinous junction of the triceps surae before stretching. Group B rested for 7 minutes before stretching. Both groups then performed identical calf stretches for 4 minutes. Treatment for both groups was conducted at the Brigham Young University Sports Injury Research Laboratory twice daily for 5 days with at least 3 hours between procedures. We analyzed the data with a 2 × 3 × 10 factorial analysis of variance with repeated measures. A Tukey post hoc test was used to identify significant differences in range of motion.
Forty college students (male = 18, female = 22, age = 20.4 ± 2.5 years) volunteered for the study.
Maximal ankle dorsiflexion range of motion was measured using an inclinometer before and after each treatment.
Immediate effects were that ultrasound and stretch increased mean dorsiflexion range of motion in all sessions significantly more than stretch alone in three treatment sessions. Residual effects were that dorsiflexion range of motion increased 3° in both groups after nine treatment sessions; however, neither group significantly outperformed the other.
As studied, an ultrasound and stretch routine may increase immediate range of motion more than stretch alone, possibly enhancing performance in practice and competition. This increased range of motion, however, is not maintained over the long term and is not more than the range of motion gained from stretching alone. A similar study using subjects with decreased range of motion after immobilization or injury should be conducted to see if the ultrasound and stretch regimen would produce lasting range-of-motion increases.
PMCID: PMC1320401  PMID: 16558501
flexibility; modalities; rehabilitation

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