Comparison of Open Kinetic Chain Knee and Hip Extension to Closed Kinetic Chain Leg Press Performance

1995 ◽  
Vol 4 (2) ◽  
pp. 99-107 ◽  
Author(s):  
John LaFree ◽  
Amy Mozingo ◽  
Teddy Worrell

The purposes of this study were to determine the relationship of isokinetic quadriceps and hip extensor peak torque to isokinetic leg press peak torque and to determine the influence of hip position (seated vs. supine) on leg press peak torque. Forty subjects (20 males and 20 females) were tested bilaterally on the isokinetic dynamometer. Subjects were tested during knee extension, hip extension, seated leg press, and supine leg press. Intraclass correlation coefficient and standard error of measurement values revealed acceptable reliability for all tests. An analysis of variance revealed significant dominant versus nondominant differences in all tests except hip extension. A repeated measures analysis of variance revealed no significant difference between seated and supine leg press peak torque. Finally, stepwise regression revealed a significant relationship between knee extension and leg press peak torques, with hip extension adding only minimally to the explained variance. These data suggest that knee extension and leg press peak torque assess similar muscle performance characteristics. Further research involving electromyographic analysis is recommended to determine the influence of other muscles on leg press force performance.

1975 ◽  
Vol 41 (2) ◽  
pp. 441-442 ◽  
Author(s):  
Ronald A. Berk

This paper presents a brief description of the generalizability theory of measurement error and its relation to analysis of variance with repeated measures. The intraclass correlation is defined in terms of analysis of variance computer program output. The usefulness of several programs is discussed.


2013 ◽  
Vol 22 (1) ◽  
pp. 59-66 ◽  
Author(s):  
Che-Hsiu Chen ◽  
Tsun-Shun Huang ◽  
Huei-Ming Chai ◽  
Mei-Hwa Jan ◽  
Jiu-Jenq Lin

Context:Recent studies have shown that the static stretch (SS) may adversely affect leg-muscle performance.Objectives:The authors examined the short-term effects of 2 stretching exercises on hamstrings muscle before and after exercise.Design:Crossover.Setting:Laboratory.Participants:9 healthy, physically active men.Interventions:There were 3 protocols in a randomized order with a 7-d interval: nonstretching (CON protocol), hamstrings static stretching (SS) with proprioceptive neuromuscular facilitation (PNF), and SS with kinesio-taping application on the hamstrings.Main Outcome Measures:Outcome measures included first-felt and maximum tolerant-felt range of motion (FROM and TROM), maximal knee-flexion peak torque (PT) at 180°/s, and hamstrings muscle stiffness.Results:Groups were not different at prestretching in terms of hamstrings flexibility, PT, and muscle stiffness. At poststretching, both stretching protocols showed significant increases in FROM and TROM (P < .05). Stiffer hamstrings muscle and decreased PT were found in both SS+PNF and CON protocols (P < .05). However, there was no significant difference in the SS+Taping protocol (P > .05).Conclusion:The stretching protocols improve hamstrings flexibility immediately, but after exercise hamstrings peak torque is diminished in the SS+PNF but not in the SS+Taping group. This means that SS+Taping can prevent negative results from exercise, which may prevent muscle injury.


2020 ◽  
Vol 24 (1) ◽  
pp. 12-18
Author(s):  
Bárbara Pessali-Marques ◽  
Gustavo H.C. Peixoto ◽  
Christian E.T. Cabido ◽  
André Gustavo P. Andrade ◽  
Sara A. Rodrigues ◽  
...  

This study aimed to investigate the bio- mechanical response of the hamstring muscles to acute stretching in dancers (D) compared to non-dancers (ND). Maximal range of motion (ROMMax) and stiffness of the hamstrings were assessed in 46 young males, 23 undergraduate students (ND) and 23 professional dancers (D). Ages of the two groups were D 21.5 ± 0.60 years; ND 27.5 ± 0.98 years). Testing was performed in two sessions, familiarization with procedures in the first session and the tests themselves (pre- and post-test and intervention) in the second, with a 24- to 48-hour interval between. The pre-test consisted of three trials of passive knee extension to the point of increased tension in the hamstrings, defined as ROMMax. The resistance torque recorded at ROMMax was defined as torqueMax. Six 30-second constant torque stretches were performed at 100% of the torqueMaxreached in the pre-test in one lower limb only (intervention), with the contralateral limb used as control. The torque measured at an identical ROM before (pre-test) and after (post-test) the intervention was defined as torqueROM, and represented stiffness in this study. Reliability of the ROMMax, torqueMax, and torqueROMwas assessed via intraclass correlation coefficients (ICC3, k) and standard error of the measurements (SEM). Comparison between dancers and non-dancers, control, and intervention conditions for all dependent variables was performed using ANOVA repeated measures followed by Tukey post hoc comparisons to highlight any interaction. The submaximal stretch intensity applied caused torqueROM to decrease in both D and ND groups (p < 0.01), indicating a decrease in stiffness, but no difference between the groups was found. A significantly greater increase in ROMMax was found for the D group compared to the ND group (p < 0.01), suggesting that other aspects in addition to MTU biomechanical adaptations may have played a role in the ROMMax increase, especially for the D group. Further research is needed to explore what those other adaptations are. Meanwhile, coaches and physical therapists should be aware that dancers may require different stretch training protocols than non-dancers.


2015 ◽  
Vol 41 (2) ◽  
pp. e19-e23 ◽  
Author(s):  
Ki-Tae Koo ◽  
Min-Ho Kim ◽  
Hae-Young Kim ◽  
Ulf M. E. Wikesjö ◽  
Jae-Ho Yang ◽  
...  

This study evaluated the effects of drill wear on bone temperature during osteotomy preparation with 3 types of drills and compared heat production between drills. The drills used in this study were titanium nitride-coated metal, tungsten carbide carbon-coated metal, and zirconia ceramic drills. An osteotomy 11 mm in depth was formed in bovine scapular bone following the manufacturer's recommended drill sequences. Drilling was performed without irrigation and repeated 20 times; temperature was measured every 5 times. Next, 200 rounds of drilling during irrigation were performed for each drill, with temperature change monitored until round 200. Analysis of variance statistics were used for analyses of the measured data. Drilling without irrigation showed significant thermal increase at all time points compared to drilling with irrigation (P &lt; .001). No significant difference was found between drill materials. Under irrigation, the frequency of previous drilling had minimal effects on thermal change. The repeated-measures analysis of variance revealed major thermal change at the initial time point (P &lt; .0001), and the multiple comparison tests revealed a significant difference in temperature between the initial drills that had been used 50 or fewer times and those that had been used more than 50 times, irrespective of the drill material. The results of this study indicate that the initial drill should be changed in osteotomy preparation with irrigation after they have been used 50 times. Irrigation may be a more critical factor for the control of temperature elevation than is the drill material.


2014 ◽  
Vol 9 (2) ◽  
pp. 358-361 ◽  
Author(s):  
Scott R. Brown ◽  
Matt Brughelli ◽  
Peter C. Griffiths ◽  
John B. Cronin

Purpose:While several studies have documented isokinetic knee strength in junior and senior rugby league players, investigations of isokinetic knee and hip strength in professional rugby union players are limited. The purpose of this study was to provide lower-extremity strength profiles and compare isokinetic knee and hip strength of professional rugby league and rugby union players.Participants:32 professional rugby league and 25 professional rugby union players.Methods:Cross-sectional analysis. Isokinetic dynamometry was used to evaluate peak torque and strength ratios of the dominant and nondominant legs during seated knee-extension/flexion and supine hip-extension/flexion actions at 60°/s.Results:Forwards from both codes were taller and heavier and had a higher body-mass index than the backs of each code. Rugby union forwards produced significantly (P < .05) greater peak torque during knee flexion in the dominant and nondominant legs (ES = 1.81 and 2.02) compared with rugby league forwards. Rugby league backs produced significantly greater hip-extension peak torque in the dominant and nondominant legs (ES = 0.83 and 0.77) compared with rugby union backs. There were no significant differences in hamstring-to-quadriceps ratios between code, position, or leg. Rugby union forwards and backs produced significantly greater knee-flexion-to-hip-extension ratios in the dominant and nondominant legs (ES = 1.49–2.26) than rugby union players.Conclusions:It seems that the joint torque profiles of players from rugby league and union codes differ, which may be attributed to the different demands of each code.


2021 ◽  
Author(s):  
Peter Sutton ◽  
Marie Ohlsson ◽  
Ulrik Röijezon

Abstract Background: Assessment of shoulder proprioception outside the laboratory in the absence of specialized equipment remains a challenge with field-based tests often lacking good reliability, validity and feasibility. This study aimed to enhance the knowledge base surrounding the assessment of shoulder proprioception and investigated the effect of fatigue on shoulder joint position sense (JPS) amongst amateur male handball players.Method: 27 healthy recreationally active participants and 13 amateur male handball players undertook two sessions of active JPS tests using laser pen technology and a calibrated 2-dimensional target to assess test-retest reliability. The active JPS test was then utilized on the subgroup of handball players who were subjected to five bouts of a repeated throwing task in order to investigate the effect of local fatigue on shoulder JPS. Results: The intraclass correlation coefficient for the active JPS test was 0.78 (95% CI = [0.57; 0.89]). Standard error of measurement between trials was 0.70° (range 0.57°-0.90°). For the throwing task, repeated measures analysis of variance revealed a significant interaction for arm x bout (F5=2.74, p=0.028) and a significant effect for arm (F1=5.85, p=0.034). Post hoc analysis showed a significant difference between throwing arm and non-throwing arm after throwing bout one (p=0.036), three (p=0.026) and four (p=0.041). Conclusion: Assessment of the active JPS test showed acceptable reliability and measurement error. Repeated throwing to fatigue decreased shoulder JPS in amateur male handball players which indicate validity of the test to identify reduced proprioception.


Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Daniela Bassi ◽  
Vivian M Arakelian ◽  
Renata G Mendes ◽  
Flavia C Caruso ◽  
José C Bonjorno Júnior ◽  
...  

Background: The prevalence of diabetes have increased globally to epidemic proportions; glycemic control and treatment remains a challenge. Concurrent aerobic and resistance training programs (CART) have been widely recommended as an important strategy to improve physiologic and functional performance. Objective: The impact of CART programs on metabolic profile, glycemic control and exercise capacity status in patients with diabetes requires additional study, which is the primary aim of the current study. Materials and Methods: We evaluated 41 patients (15 female and 19 male, 50.8±7 years) with a confirmed diagnosis of diabetes. The subjects were randomized in two groups: sedentary group (SG) and CART group (CART-G). CART was performed 12 weeks, 3 times a week for approximately 1 hour per session (30 minutes aerobic and 30 minutes resistance). Body habitus was assessed by body mass index, waist circumference, and skinfolds. Peripheral muscular strength was evaluated by an isokinetic dynamometer and pulmonary gas exchange was measured breath-by-breath, using a portable telemetric system during maximal incremental exercise testing on a cycle ergometer. Statistical analysis included Shapiro-Wilk test follow by ANOVA two way repeated measures. Results: We observed a decrease in HbA1c (8.1±1.6 to 7.3±1.2%), cholesterol (198.38.1±50.3 to 186.8±35.1 mg/dL) and HOMA IR (6.4±6.8 to 5.0±1.4) in the CART-G compared to the SG. There was no significant difference in fasting plasma glucose. Although body weight did not significantly change after training, skinfold measurements indicated decreased body fat in the CART-G only. CART significantly enhanced muscle strength (p<0.05) (peak torque: 135.5±4 to 159.7±47.7 N.m) compared to the SG (Peak torque: 145.3±47.9 to 143±42.2 N.m). CART was also associated with a significant increase in peak oxygen consumption, from 22.9±6.1 to 27.2±4.7 ml•kg –1 •min –1 compared to the SG, from 21.7±4.5 to 21±3.3 ml•kg –1 •min –1 as well as the maximal workload (124.6±29.1 to 149.9±29 watts) compared to the SG (123.6±36.9 to 122.1±32.9 watts). Conclusion: We concluded that CART is an important intervention strategy, producing both physiologic and functional improvements, in patients with diabetes.


2017 ◽  
Vol 32 (3) ◽  
pp. 305-310 ◽  
Author(s):  
James M. Burgert ◽  
Arthur D. Johnson ◽  
Jose Garcia-Blanco ◽  
Lawrence V. Fulton ◽  
Michael J. Loughren

AbstractIntroductionThe American Heart Association (AHA; Dallas, Texas USA) and European Resuscitation Council (Niel, Belgium) cardiac arrest (CA) guidelines recommend the intraosseous (IO) route when intravenous (IV) access cannot be obtained. Vasopressin has been used as an alternative to epinephrine to treat ventricular fibrillation (VF).Hypothesis/ProblemLimited data exist on the pharmacokinetics and resuscitative effects of vasopressin administered by the humeral IO (HIO) route for treatment of VF. The purpose of this study was to evaluate the effects of HIO and IV vasopressin, on the occurrence, odds, and time of return of spontaneous circulation (ROSC) and pharmacokinetic measures in a swine model of VF.MethodsTwenty-seven Yorkshire-cross swine (60 to 80 kg) were assigned randomly to three groups: HIO (n=9), IV (n=9), and a control group (n=9). Ventricular fibrillation was induced and untreated for two minutes. Chest compressions began at two minutes post-arrest and vasopressin (40 U) administered at four minutes post-arrest. Serial blood specimens were collected for four minutes, then the swine were resuscitated until ROSC or 29 post-arrest minutes elapsed.ResultsFisher’s Exact test determined ROSC was significantly higher in the HIO 5/7 (71.5%) and IV 8/11 (72.7%) groups compared to the control 0/9 (0.0%; P=.001). Odds ratios of ROSC indicated no significant difference between the treatment groups (P=.68) but significant differences between the HIO and control, and the IV and control groups (P=.03 and .01, respectively). Analysis of Variance (ANOVA) indicated the mean time to ROSC for HIO and IV was 621.20 seconds (SD=204.21 seconds) and 554.50 seconds (SD=213.96 seconds), respectively, with no significant difference between the groups (U=11; P=.22). Multivariate Analysis of Variance (MANOVA) revealed the maximum plasma concentration (Cmax) and time to maximum concentration (Tmax) of vasopressin in the HIO and IV groups was 71753.9 pg/mL (SD=26744.58 pg/mL) and 61853.7 pg/mL (SD=22745.04 pg/mL); 111.42 seconds (SD=51.3 seconds) and 114.55 seconds (SD=55.02 seconds), respectively. Repeated measures ANOVA indicated no significant difference in plasma vasopressin concentrations between the treatment groups over four minutes (P=.48).ConclusionsThe HIO route delivered vasopressin effectively in a swine model of VF. Occurrence, time, and odds of ROSC, as well as pharmacokinetic measurements of HIO vasopressin, were comparable to IV.BurgertJM, JohnsonAD, Garcia-BlancoJ, FultonLV, LoughrenMJ. The resuscitative and pharmacokinetic effects of humeral intraosseous vasopressin in a swine model of ventricular fibrillation. Prehosp Disaster Med. 2017;32(3):305–310.


2017 ◽  
Vol 26 (4) ◽  
pp. 216-222 ◽  
Author(s):  
In-cheol Jeon ◽  
Oh-yun Kwon ◽  
Jong-hyuck Weon ◽  
Ui-jae Hwang ◽  
Sung-hoon Jung

Context:Prone hip extension has been recommended for strengthening the back and hip muscles. Previous studies have investigated prone hip extension conducted with subjects on the floor in the prone position. However, no study has compared 3 different table hip-extension (THE) positions in terms of the activities of the back- and hip-joint muscles with lumbopelvic motion.Objective:To identify more effective exercises for strengthening the gluteus maximus (GM) by comparing 3 different exercises (THE alone, THE with the abdominal drawing-in maneuver [THEA], and THEA with chair support under the knee [THEAC]) based on electromyographic muscle activity and pelvic compensation.Design:Repeated-measure within-subject intervention.Setting:University research laboratory.Participants:16 healthy men.Main Outcome Measures:Surface electromyography (EMG) was used to obtain data on the GM, erector spinae (ES), multifidus, biceps femoris (BF), and semitendinosus (ST). Pelvic compensation was monitored using an electromagnetic motion-tracking device. Exertion during each exercise was recorded. Any significant difference in electromyographic muscle activity and pelvic motion among the 3 conditions (THE vs THEA vs THEAC) was assessed using a 1-way repeated-measures analysis of variance (ANOVA) with Bonferroni post hoc test.Results:The muscle activities recorded by EMG differed significantly among the 3 exercises (P < .01). GM activity was increased significantly during THEAC (P < .01). There was a significant difference in lumbopelvic kinematics in terms of anterior tilting (F = 19.49, P < .01) and rotation (F= 27.38, P < .01) among the 3 exercises.Conclusions:The THEAC exercise was the most effective for strengthening the GM without overactivity of the ES, BF, and ST muscles and lumbopelvic compensation compared with THE and THEA.


2021 ◽  
pp. 030573562198897
Author(s):  
Aaron Lohmeyer

The primary purposes of this study were (1) to determine the effect of three encoding conditions (singing, playing, studying silently) on participants’ music memorization accuracy; (2) to examine potential differences between choral, jazz, and concert band musicians’ accuracy in completing the music memorization task; and (3) to determine whether ensemble affiliation yielded any performance advantages among the three presentation conditions. Three folk melodies were selected for memorization under the three encoding conditions. Participants ( N = 81) had 75 s to commit each melody to memory while studying silently, singing, or playing on a keyboard. Participants then notated the three melodies using conventional staff notation. A two-way analysis of variance (ANOVA) with repeated measures on one factor revealed significant differences based on participants’ ensemble affiliation. A Tukey’s honest significant difference (HSD) post hoc test revealed the jazz group had higher accuracy scores than the band group. No significant differences were found based on encoding conditions, and no significant interactions were found between the encoding conditions and ensemble groups. The experiment is framed by questions related to memory, reading, and differing notions of literacy.


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