Proprioceptive Neuromuscular Facilitation Decreases Muscle Activity during the Stretch Reflex in Selected Posterior Thigh Muscles

2000 ◽  
Vol 9 (4) ◽  
pp. 269-278 ◽  
Author(s):  
Allyson M. Carter ◽  
Stephen J. Kinzey ◽  
Linda F. Chitwood ◽  
Judith L Cole

Context:Proprioceptive neuromuscular facilitation (PNF) is commonly used before competition to increase range of motion. It is not known how it changes muscle response to rapid length changes.Objective:To determine whether PNF alters hamstring muscle activity during response to rapid elongation.Design:2 X 2 factorial.Setting:Laboratory.Participants:Twenty-four women; means: 167.27 cm, 58.92 kg, 21.42 y, 18.41% body fat, 21.06 kg/m2BMI.intervention:Measurements before and after either rest or PNF were compared.Main Outcome Measures:Average muscle activity immediately after a rapid and unexpected stretch, 3 times pretreatment and posttreatment, averaged into 2 pre-and post- measures.Results:PNF caused decreased activity in the biceps femoris during response to a sudden stretch (P= .04). No differences were found in semitendinosus activity (P= .35).Conclusions:Decreased muscle activity likely results from acute desensitization of the muscle spindle, which might increase risk of muscle and tendon injury.

2014 ◽  
Vol 23 (2) ◽  
pp. 107-122 ◽  
Author(s):  
W. Matthew Silvers ◽  
Eadric Bressel ◽  
D. Clark Dickin ◽  
Garry Killgore ◽  
Dennis G. Dolny

Context:Muscle activation during aquatic treadmill (ATM) running has not been examined, despite similar investigations for other modes of aquatic locomotion and increased interest in ATM running.Objectives:The objectives of this study were to compare normalized (percentage of maximal voluntary contraction; %MVC), absolute duration (aDUR), and total (tACT) lower-extremity muscle activity during land treadmill (TM) and ATM running at the same speeds.Design:Exploratory, quasi-experimental, crossover design.Setting:Athletic training facility.Participants:12 healthy recreational runners (age = 25.8 ± 5 y, height = 178.4 ± 8.2 cm, mass = 71.5 ± 11.5 kg, running experience = 8.2 ± 5.3 y) volunteered for participation.Intervention:All participants performed TM and ATM running at 174.4, 201.2, and 228.0 m/min while surface electromyographic data were collected from the vastus medialis, rectus femoris, gastrocnemius, tibialis anterior, and biceps femoris.Main Outcome Measures:For each muscle, a 2 × 3 repeated-measures ANOVA was used to analyze the main effects and environment–speed interaction (P ≤ .05) of each dependent variable: %MVC, aDUR, and tACT.Results:Compared with TM, ATM elicited significantly reduced %MVC (−44.0%) but increased aDUR (+213.1%) and tACT (+41.9%) in the vastus medialis, increased %MVC (+48.7%) and aDUR (+128.1%) in the rectus femoris during swing phase, reduced %MVC (−26.9%) and tACT (−40.1%) in the gastrocnemius, increased aDUR (+33.1%) and tACT (+35.7%) in the tibialis anterior, and increased aDUR (+41.3%) and tACT (+29.2%) in the biceps femoris. At faster running speeds, there were significant increases in tibialis anterior %MVC (+8.6−15.2%) and tACT (+12.7−17.0%) and rectus femoris %MVC (12.1−26.6%; swing phase).Conclusion:No significant environment–speed interaction effects suggested that observed muscle-activity differences between ATM and TM were due to environmental variation, ie, buoyancy (presumed to decrease %MVC) and drag forces (presumed to increase aDUR and tACT) in the water.


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.


2016 ◽  
Vol 64 (3) ◽  
pp. 505
Author(s):  
Nicolás Rojas-Barrionuevo ◽  
Mercedes Vernetta-Santana ◽  
Jesús López-Bedoya

Introduction: Jumping capacity, a distinctive technical skill of tumbling gymnasts, is associated to a successful performance in training and competition; hence the need for an individualized, precise and localized assessment of the most demanded muscle structures.Objective: To assess muscle response of the flexo-extension structure in the knee joint and the extension of the ankle joint in a sample of 12 high-performance male gymnasts.Materials and methods: An acrobatic training protocol including sets of forward somersault in tumbling track was conducted. The contraction time, delay time and deformation of muscle belly were evaluated, and the muscular response speed was calculated using tensiomyography before and after the training intervention in different periods of time.Results: Significant differences were found (p<0.05) according to the muscle group involved, where rectus femoris and biceps femoris presented greater enhancement and shortening of the contraction and delay time. Major differences appeared between agonist-antagonist muscles (vastus lateralis-biceps femoris) (p<0.05) due to a decrease in the contraction and delay speed in vastus medialis (p<0.001).Conclusions: Tensiomyography allows estimating the states of activation-enhancing of the musculature responsible of jumping in tumblers, as well as planning the training based on the state of muscle fatigue.


Author(s):  
Pierre Clos ◽  
Romuald Lepers

Background: This study tested muscle activity (EMG) and perception of effort in eccentric (ECC) and concentric (CON) cycling before and after four sessions of both. Methods: Twelve volunteers naïve to ECC cycling attended the laboratory six times. On day 1, they performed a CON cycling peak power output (PPO) test. They then carried-out four sessions comprising two sets of 1 to 1.5-min cycling bouts at 5 intensities (30, 45, 60, 75, and 90% PPO) in ECC and CON cycling. On day 2 and day 6 (two weeks apart), EMG root mean square of the vastus lateralis (VL), rectus femoris (RF), biceps femoris (BF), and soleus (SOL) muscles, was averaged from 15 to 30 s within each 1-min bout and perception of effort was asked after 45 s. Results: Before the four cycling sessions, while VL EMG was lower in ECC than CON cycling, most variables were not different. Afterwards, ECC cycling exhibited lower RF EMG at 75 and 90% PPO (all p < 0.02), lower VL and BF EMG at all exercise intensities (all p < 0.02), and inferior SOL EMG (all p < 0.04) except at 45% PPO (p = 0.07). Perception of effort was lower in ECC cycling at all exercise intensities (all p < 0.03) but 60% PPO (p = 0.11). Conclusions: After four short sessions of ECC cycling, the activity of four leg muscles and perception of effort became lower in ECC than in CON cycling at most of five power outputs, while they were similar before.


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 ◽  
Vol 6 (1) ◽  
pp. 26
Author(s):  
Eleftherios Kellis ◽  
Athina Konstantinidou ◽  
Athanasios Ellinoudis

Muscle morphology is an important contributor to hamstring muscle injury and malfunction. The aim of this study was to examine if hamstring muscle-tendon lengths differ between various measurement methods as well as if passive length changes differ between individual hamstrings. The lengths of biceps femoris long head (BFlh), semimembranosus (SM), and semitendinosus (ST) of 12 healthy males were determined using three methods: Firstly, by identifying the muscle attachments using ultrasound (US) and then measuring the distance on the skin using a flexible ultrasound tape (TAPE-US). Secondly, by scanning each muscle using extended-field-of view US (EFOV-US) and, thirdly, by estimating length using modelling equations (MODEL). Measurements were performed with the participant relaxed at six combinations of hip (0°, 90°) and knee (0°, 45°, and 90°) flexion angles. The MODEL method showed greater BFlh and SM lengths as well as changes in length than US methods. EFOV-US showed greater ST and SM lengths than TAPE-US (p < 0.05). SM length change across all joint positions was greater than BFlh and ST (p < 0.05). Hamstring length predicted using regression equations is greater compared with those measured using US-based methods. The EFOV-US method yielded greater ST and SM length than the TAPE-US method. SM showed the highest change in length at different hip and knee joint positions.


2017 ◽  
Vol 123 (4) ◽  
pp. 884-893 ◽  
Author(s):  
Luis Peñailillo ◽  
Anthony J. Blazevich ◽  
Kazunori Nosaka

This study compared muscle-tendon behavior, muscle oxygenation, and muscle activity between eccentric and concentric cycling exercise at the same work output to investigate why metabolic demand is lower during eccentric cycling than with concentric cycling. Eleven untrained men (27.1 ± 7.0 y) performed concentric cycling (CONC) and eccentric cycling (ECC) for 10 min (60 rpm) at 65% of the maximal concentric cycling power output (191 ± 45 W) 4 wk apart. During cycling, oxygen consumption (V̇o2), heart rate (HR), vastus lateralis (VL) tissue total hemoglobin (tHb), and oxygenation index (TOI) were recorded, and muscle-tendon behavior was assessed using ultrasonography. The surface electromyogram (EMG) was recorded from VL, vastus medialis (VM), rectus femoris (RF), and biceps femoris (BF) muscles, and cycling torque and knee joint angle during each revolution were also recorded. Average V̇o2 (−65 ± 7%) and HR (−35 ± 9%) were lower and average TOI was greater (16 ± 1%) during ECC than CONC, but tHb was similar between bouts. Positive and negative cycling peak crank torques were greater (32 ± 21 and 48 ± 24%, respectively) during ECC than CONC, but muscle-tendon unit and fascicle and tendinous tissue length changes during pedal revolutions were similar between CONC and ECC. VL, VM, RF, and BF peak EMG amplitudes were smaller (24 ± 15, 22 ± 18, 16 ± 17, and 18 ± 9%, respectively) during ECC than CONC. These results suggest that the lower metabolic cost of eccentric compared with concentric cycling was due mainly to a lower level of muscle activation per torque output. NEW & NOTEWORTHY This study shows that lower oxygen consumption of eccentric compared with concentric cycling at the same workload is explained by lower muscle activity of agonist and antagonist muscles during eccentric compared with during concentric cycling.


2020 ◽  
Author(s):  
Luis Mochizuki ◽  
Juliana Pennone ◽  
Aline Bigongiari ◽  
Renata Garrido Cosme ◽  
Monique Oliveira Baptista Cajueiro ◽  
...  

AbstractThis study investigated the muscle activity during the preparatory (anticipatory postural adjustment, APA), execution (online postural adjustments, OPA), and compensatory (compensatory postural adjustment, CPA) phases during standing with eyes opened or closed on an elevated platform. Eight healthy young women stood in the upright position, with eyes opened or closed, and did as-fast-as-they-could shoulder flexions on the ground and on 1-m-height-portable-elevated-platform. The surface EMG of trunk (lumbar extensor, and rectus abdominis) and lower limb (rectus femoris, biceps femoris, tibialis anterior and gastrocnemius lateralis) muscles during this task were recorded (1 kHz sampling frequency) and compared during these three phases. Analysis of variance was applied to compare the effects of height (floor and elevated platform), vision (open and closed), and postural adjustment (APA, OPA and CPA) into the activity of each muscle. These muscles were more active during OPA (p<0.0001) and less active during APA. On the elevated platform, these postural muscles presented more activty during APA (p<0.001). During the most stable condition (on the ground with eyes opened), muscle activity during APA and OPA was negatively correlated, and not correlated between OPA and CPA. Our results suggest postural control adapts to sensory, motor, and cognitive conditions. Therefore, the increased demand for postural control, generated due to the height of the support base, provokes the need for greater flexibility of postural synergies and causes a change in muscle activity.Summary StatementWe discuss how postural muscle activity behaves before and after a fast upper arms movement when someone stands on a elevated platform or on the ground.


2020 ◽  
Vol 17 (4) ◽  
pp. 437-445
Author(s):  
Irene Ciancarelli ◽  
Giovanni Morone ◽  
Marco Iosa ◽  
Stefano Paolucci ◽  
Loris Pignolo ◽  
...  

Background: Limited studies concern the influence of obesity-induced dysregulation of adipokines in functional recovery after stroke neurorehabilitation. Objective: To investigate the relationship between serum leptin, resistin, and adiponectin and functional recovery before and after neurorehabilitation of obese stroke patients. The adipokine potential significance as prognostic markers of rehabilitation outcomes was also verified. Methods: Twenty obese post-acute stroke patients before and after neurorehabilitation and thirteen obese volunteers without-stroke, as controls, were examined. Adipokines were determined by commercially available enzyme-linked immunosorbent assay (ELISA) kits. Functional deficits were assessed before and after neurorehabilitation with the Barthel Index (BI), modified Rankin Scale (mRS), and Functional Independence Measure (FIM). Results: Compared to controls, higher leptin and resistin values and lower adiponectin values were observed in stroke patients before neurorehabilitation and no correlations were found between adipokines and clinical outcome measures. Neurorehabilitation was associated with improved scores of BI, mRS, and FIM. After neurorehabilitation, decreased values of Body Mass Index (BMI) and resistin together increased adiponectin were detected in stroke patients, while leptin decreased but not statistically. Comparing adipokine values assessed before neurorehabilitation with the outcome measures after neurorehabilitation, correlations were observed for leptin with BI-score, mRS-score, and FIM-score. No other adipokine levels nor BMI assessed before neurorehabilitation correlated with the clinical measures after neurorehabilitation. The forward stepwise regression analysis identified leptin as prognostic factor for BI, mRS, and FIM. Conclusions: Our data show the effectiveness of neurorehabilitation in modulating adipokines levels and suggest that leptin could assume the significance of biomarker of functional recovery.


Author(s):  
Eun-Dong Jeong ◽  
Chang-Yong Kim ◽  
Nack-Hwan Kim ◽  
Hyeong-Dong Kim

BACKGROUND: The cranio-cervical flexion exercise and sub-occipital muscle inhibition technique have been used to improve a forward head posture among neck pain patients with straight leg raise (SLR) limitation. However, little is known about the cranio-vertebral angle (CVA) and cervical spine range of motion (CROM) after applying stretching methods to the hamstring muscle. OBJECTIVE: To compare the immediate effects of static stretching and proprioceptive neuromuscular facilitation stretching on SLR, CVA, and CROM in neck pain patients with hamstring tightness. METHODS: 64 subjects were randomly allocated to the static stretching (n1= 32) or proprioceptive neuromuscular facilitation (n2= 32) stretching group. The SLR test was performed to measure the hamstring muscle’s flexibility and tightness between the two groups, with CROM and CVA also being measured. The paired t-test was used to compare all the variables within each group before and after the intervention. The independent t-test was used to compare the two groups before and after the stretching exercise. RESULTS: There were no between-group effects for any outcome variables (P> 0.05). However, all SLR, CVA, and CROM outcome variables were significantly improved within-group (P< 0.05). CONCLUSIONS: There were no between-group effects for any outcome variable; however, SLR, CVA, and CROM significantly improved within-group after the one-session intervention in neck pain patients with hamstring tightness.


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