Appropriate Resistance Intensity and Effective Exercise for Activation of Infraspinatus

2019 ◽  
Vol 40 (09) ◽  
pp. 569-575
Author(s):  
Il-Young Yu ◽  
Se-Il Oh ◽  
Won-Jeong Jung ◽  
Jaeseop Oh
Keyword(s):  
Muscle Activity ◽  
Surface Electromyography ◽  
High Intensity ◽  
Activity Ratio ◽  
External Rotation ◽  
Deltoid Muscle ◽  
Selective Activation ◽  
Low Intensity ◽  
Medium Intensity ◽  
Healthy Males

AbstractWe investigated the muscle activities of the infraspinatus and posterior deltoid, as well as the ratio of the infraspinatus to posterior deltoid muscle activities, in response to 3 resistance intensities during prone external rotation (PER) and sitting external rotation (SITER) exercises. Fifteen healthy males participated; the subjects performed two exercises randomly at three resistance intensity levels: 1) low intensity (10–20%); 2) medium intensity (45–55%); 3) high intensity (60–70%). Surface electromyography was used to measure the activities of the infraspinatus and posterior deltoid muscles. The activities of the infraspinatus and posterior deltoid increased significantly as the resistance intensity increased during both PER and SITER exercises (p<0.001). The infraspinatus-to-posterior deltoid activity ratio increased as the resistance intensity decreased. Whereas the muscle activity ratio was highest under low and medium intensity during PER and SITER, respectively, and the muscle activity ratio was significantly increased at medium intensity compared with high intensity during both PER (p=0.023) and SITER (p=0.001). Our results suggest that low to medium intensity is the appropriate resistance intensity for selective activation of the infraspinatus. In addition, our results suggest that PER and SITER are effective for strengthening the infraspinatus.

The Relationships Between External and Internal Workloads During Basketball Training and Games

2020 ◽  
Vol 15 (8) ◽  
pp. 1081-1086
Author(s):  
Jordan L. Fox ◽  
Cody J. O’Grady ◽  
Aaron T. Scanlan
Keyword(s):  
Heart Rate ◽  
High Intensity ◽  
Perceived Exertion ◽  
Movement Analysis ◽  
Rating Of Perceived Exertion ◽  
Large Games ◽  
Workload Management ◽  
Low Intensity ◽  
Medium Intensity ◽  
Selection Of

Purpose: To investigate the relationships between external and internal workloads using a comprehensive selection of variables during basketball training and games. Methods: Eight semiprofessional, male basketball players were monitored during training and games for an entire season. External workload was determined as PlayerLoad™: total and high-intensity accelerations, decelerations, changes of direction, and jumps and total low-intensity, medium-intensity, high-intensity, and overall inertial movement analysis events. Internal workload was determined using the summated-heart-rate zones and session rating of perceived exertion models. The relationships between external and internal workload variables were separately calculated for training and games using repeated-measures correlations with 95% confidence intervals. Results: PlayerLoad was more strongly related to summated-heart-rate zones (r = .88 ± .03, very large [training]; r = .69 ± .09, large [games]) and session rating of perceived exertion (r = .74 ± .06, very large [training]; r = .53 ± .12, large [games]) than other external workload variables (P < .05). Correlations between total and high-intensity accelerations, decelerations, changes of direction, and jumps and total low-intensity, medium-intensity, high-intensity, and overall inertial movement analysis events and internal workloads were stronger during training (r = .44–.88) than during games (r = .15–.69). Conclusions: PlayerLoad and summated-heart-rate zones possess the strongest dose–response relationship among a comprehensive selection of external and internal workload variables in basketball, particularly during training sessions compared with games. Basketball practitioners may therefore be able to best anticipate player responses when prescribing training drills using these variables for optimal workload management across the season.

Relationships Between External- and Internal-Workload Variables in an Elite Female Netball Team and Between Playing Positions

2020 ◽  
Vol 15 (6) ◽  
pp. 841-846 ◽  
Author(s):  
Marni J. Simpson ◽  
David G. Jenkins ◽  
Aaron T. Scanlan ◽  
Vincent G. Kelly
Keyword(s):  
Heart Rate ◽  
High Intensity ◽  
Perceived Exertion ◽  
Vertical Direction ◽  
Forward Direction ◽  
Ratings Of Perceived Exertion ◽  
Low Intensity ◽  
Medium Intensity ◽  
Movement Unit

Purpose: To examine relationships between external- and internal-workload variables in an elite female netball team, with consideration of positional differences. Methods: Nine elite female netball athletes had their weekly workloads monitored across their preseason and competition phases of a season. Internal workload was determined using summated heart-rate (HR) zones and session ratings of perceived exertion (sRPE), whereas external workload was determined using inertial movement units and included absolute PlayerLoad (PL), relative PL (PL per minute), accelerations (ACCEL), decelerations (DECEL), jumps, changes of direction (COD), high-intensity events, medium-intensity events, low-intensity events, PL in the forward direction, PL in the sideways direction, and PL in the vertical direction. Relationships between external- and internal-workload variables in the team and relative to playing position were examined. Results: Across the team, the strongest external workloads that correlated with summated HR zones were PL (r = .65), COD (r = .64), ACCEL (r = .61), and DECEL (r = .61). The strongest external workloads that correlated with sRPE were COD (r = .79), followed by jumps (r = .76), ACCEL (r = .75), and DECEL (r = .75). For all positions, except-goal shooter, the strongest correlation was between PL and sRPE (r = .88–.94). In the goal-shooter position, the strongest correlation was between summated HR zones and DECEL (r = .89). Conclusions: The inertial movement unit-derived external-workload variables are strongly related to common internal-workload variables. In particular, COD and sRPE appear to provide a good monitoring combination of external and internal training loads for elite netball players.

scholarly journals Soil Element Stoichiometry Drives Bacterial Community Composition Following Thinning in A Larix Plantation in the Subalpine Regions of Northern China

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 261
Author(s):  
Mengke Cai ◽  
Xinhao Peng ◽  
Xiaoqin Cheng ◽  
Li Liu ◽  
Shiping Xing ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Community Composition ◽  
High Intensity ◽  
Bacterial Communities ◽  
Soil Resource ◽  
Low Intensity ◽  
Medium Intensity ◽  
Elemental Stoichiometry ◽  
Tree Removal ◽  
Bacterial Groups

It is well established that forest thinning alters aboveground plant community composition and soil resource availability. However, how it regulates the composition and diversity of belowground microbial communities remains unclear. To quantify the effects of thinning on soil bacterial groups and the underlying mechanisms of these effects, this research was conducted in a Larix principis-rupprechtii Mayr. plantation with various thinning intensities, including a control (0% tree removal), a low-intensity treatment (15% tree removal), a medium-intensity treatment (35% tree removal), and a high-intensity treatment (50% tree removal). Compared to the control, the medium and high intensity thinning treatments significantly improved soil moisture, nutrient concentrations (including soil total carbon, nitrogen, phosphorus, and ammonium nitrogen), microbial biomass, and elemental stoichiometry ratios. The abundance and diversity of bacterial communities peaked in the medium-intensity treatment. Thinning also had strong effects on dominant bacterial groups at the phylum level. For instance, Bacteroidetes and Nitrospirae were significantly increased in the medium-intensity treatment (MIT), while the Gemmatimonadetes were significantly decreased in the low-intensity treatment (LIT). Combining Spearman correlation analysis and redundancy analysis demonstrated that thinning could facilitate the assembly of unique bacterial communities, and these shifts in microorganisms could probably be attributed to corresponding changes in soil resource stoichiometry. In conclusion, this study provides novel evidence that rational thinning could promote belowground bacterial community diversity and that elemental stoichiometry is an important indicator in shaping forest soil bacterial communities.

scholarly journals Effects of Vibration Intensity, Exercise, and Motor Impairment on Leg Muscle Activity Induced by Whole-Body Vibration in People With Stroke

2015 ◽  
Vol 95 (12) ◽  
pp. 1617-1627 ◽  
Author(s):  
Lin-Rong Liao ◽  
Gabriel Y.F. Ng ◽  
Alice Y.M. Jones ◽  
Raymond C.K. Chung ◽  
Marco Y.C. Pang
Keyword(s):  
Muscle Activity ◽  
High Intensity ◽  
Whole Body Vibration ◽  
Motor Impairment ◽  
Chronic Stroke ◽  
Whole Body ◽  
Emg Activity ◽  
Body Vibration ◽  
Low Intensity ◽  
Leg Muscle

Background Whole-body vibration (WBV) has increasingly been used as an adjunct treatment in neurological rehabilitation. However, how muscle activation level changes during exposure to different WBV protocols in individuals after stroke remains understudied. Objective The purpose of this study was to examine the influence of WBV intensity on the magnitude of biceps femoris (BF) and tibialis anterior (TA) muscle activity and its interaction with exercise and with severity of motor impairment and spasticity among individuals with chronic stroke. Methods Each of the 36 individuals with chronic stroke (mean age=57.3 years, SD=10.7) performed 8 different static exercises under 3 WBV conditions: (1) no WBV, (2) low-intensity WBV (frequency=20 Hz, amplitude=0.60 mm, peak acceleration=0.96g), and (3) high-intensity WBV (30 Hz, 0.44 mm, 1.61g). The levels of bilateral TA and BF muscle activity were recorded using surface electromyography (EMG). Results The main effect of intensity was significant. Exposure to the low-intensity and high-intensity protocols led to a significantly greater increase in normalized BF and TA muscle electromyographic magnitude in both legs compared with no WBV. The intensity × exercise interaction also was significant, suggesting that the WBV-induced increase in EMG activity was exercise dependent. The EMG responses to WBV were similar between the paretic and nonparetic legs and were not associated with level of lower extremity motor impairment and spasticity. Limitations Leg muscle activity was measured during static exercises only. Conclusions Adding WBV during exercise significantly increased EMG activity in the TA and BF muscles. The EMG responses to WBV in the paretic and nonparetic legs were similar and were not related to degree of motor impairment and spasticity. The findings are useful for guiding the design of WBV training protocols for people with stroke.

scholarly journals Effect of Selective Muscle Training Using Visual Emg Biofeedback on Infraspinatus and Posterior Deltoid

2014 ◽  
Vol 44 (1) ◽  
pp. 83-90 ◽  
Author(s):  
One-bin Lim ◽  
Jeong-ah Kim ◽  
Si-jeong Song ◽  
Heon-seock Cynn ◽  
Chung-hwi Yi
Keyword(s):  
Activity Ratio ◽  
External Rotation ◽  
Deltoid Muscle ◽  
Surface Emg ◽  
Emg Biofeedback ◽  
Emg Activity ◽  
Muscle Training ◽  
Effective Training ◽  
Shoulder External Rotation ◽  
Asymptomatic Subjects

Abstract We investigated the effects of visual electromyography (EMG) biofeedback during side-lying shoulder external rotation exercise on the EMG amplitude for the posterior deltoid, infraspinatus, and infraspinatus/posterior deltoid EMG activity ratio. Thirty-one asymptomatic subjects were included. Subjects performed side-lying shoulder external rotation exercise with and without visual EMG biofeedback. Surface EMG was used to collect data from the posterior deltoid and infraspinatus muscles. The visual EMG biofeedback applied the pre-established threshold to prevent excessive posterior deltoid muscle contraction. A paired t-test was used to determine the significance of the measurements between without vs. with visual EMG biofeedback. Posterior deltoid activity significantly decreased while infraspinatus activity and the infraspinatus/posterior activity ratio significantly increased during side-lying shoulder external rotation exercise with visual EMG biofeedback. This suggests that using visual EMG biofeedback during shoulder external rotation exercise is a clinically effective training method for reducing posterior deltoid activity and increasing infraspinatus activity.

Positional Differences in Match Running Performance and Physical Collisions in Men Rugby Sevens

2014 ◽  
Vol 9 (2) ◽  
pp. 316-323 ◽  
Author(s):  
Luis Suarez-Arrones ◽  
Carlos Arenas ◽  
Guillermo López ◽  
Bernardo Requena ◽  
Oliver Terrill ◽  
...  
Keyword(s):  
High Intensity ◽  
Training Programs ◽  
Video Recording ◽  
Substantial Decrease ◽  
Gps Technology ◽  
Low Intensity ◽  
Total Distance ◽  
Medium Intensity ◽  
The Mean ◽  
Fitness Training

Purpose:This study describes the physical match demands relative to positional group in male rugby sevens.Methods:Ten highly trained players were investigated during competitive matches (N = 23) using GPS technology, heart rate (HR), and video recording.Results:The relative distance covered by the players throughout the match was 102.3 ± 9.8 m/min. As a percentage of total distance, 35.8% (36.6 ± 5.9 m/min) was covered walking, 26.0% (26.6 ± 5.5 m/min) jogging, 10.0% (10.2 ± 2.4 m/min) running at low intensity, 14.2% (14.5 ± 4.0 m/min) at medium intensity, 4.6% (4.7 ± 1.6 m/min) at high intensity, and 9.5% (9.7 ± 3.7 m/min) sprinting. For the backs, a substantial decrease in total distance and distance covered at low, medium, and high intensity was observed in the second half. Forwards exhibited a substantial decrease in the distance covered at medium intensity, high intensity, and sprinting in the 2nd half. Backs covered substantially more total distance at medium and sprinting speeds than forwards. In addition, the maximum length of sprint runs was substantially greater for the backs than forwards. On the contrary, forwards performed more tackles. The mean HR during the match in backs and forwards was similar, with the exception of time spent at HR intensities >90%HRmax, which was substantially higher in forwards.Conclusion:These findings provide a description of the different physical demands placed on rugby sevens backs and forwards. This information may be helpful in the development of positional and/or individualized physical-fitness training programs.

Effects of 3 Infraspinatus Muscle Strengthening Exercises on Isokinetic Peak Torque and Muscle Activity

2019 ◽  
Vol 28 (3) ◽  
pp. 229-235 ◽  
Author(s):  
Il-young Yu ◽  
Dong-kyu Lee ◽  
Myoung-Joo Kang ◽  
Jae-seop Oh
Keyword(s):  
Muscle Strength ◽  
Muscle Contraction ◽  
Muscle Activity ◽  
Repeated Measures ◽  
External Rotation ◽  
Peak Torque ◽  
Deltoid Muscle ◽  
Repeated Measures Design ◽  
Infraspinatus Muscle ◽  
Main Effect

Context: The infraspinatus muscle plays a particularly important role in producing primary external rotation (ER) torque and dynamic stability of the shoulder joint. Previous studies have reported that prone external rotation with horizontal abduction (PER), side-lying wiper exercise (SWE), and standing external rotation (STER) were effective exercises for strengthening the infraspinatus. However, we do not have enough knowledge about changes in muscle strength and dynamic muscle activity in each exercise under dynamic conditions. Objective: To compare the ER muscle strength, muscle activity among exercise methods and between muscle contraction types during 3 different exercises. Design: Repeated measures design in which ER muscle strength and muscle activities data were collected from subjects under 3 exercise conditions. Setting: Outpatient clinic. Participants: A total of 15 healthy men with no shoulder, neck, or upper-extremity pain were participated. Intervention: The subjects performed 3 different exercises randomly in concentric and eccentric using a Biodex dynamometer at an angular velocity of 60°/s. Main Outcome Measures: The ER peak torque (PT) data was collected and surface electromyography was used to measure the activity of the infraspinatus and posterior deltoid muscles and infraspinatus to posterior deltoid muscle activity ratio. Results: There was significant main effect for muscle contraction type in ER PT (P < .05). The concentric PT was greater during PER (P < .05) and SWE (P < .05) compared with eccentric. The main effect for exercise was found in ER PT and muscle activity (P < .05). The ER PT and infraspinatus muscle activity were the largest increased during PER whereas the lowest during STER in both concentric and eccentric (P < .05). Conclusion: The results of this study suggest that PER is an exercise for strengthening the infraspinatus muscle effectively.

scholarly journals Evaluation of the Biomechanical Parameters of Human-Wheelchair Systems during Ramp Climbing with the Use of a Manual Wheelchair with Anti-Rollback Devices

2020 ◽  
Vol 10 (23) ◽  
pp. 8757
Author(s):  
Bartosz Wieczorek ◽  
Mateusz Kukla ◽  
Dominik Rybarczyk ◽  
Łukasz Warguła
Keyword(s):  
Muscle Activity ◽  
Surface Electromyography ◽  
Mechanical Energy ◽  
Deltoid Muscle ◽  
Cycle Duration ◽  
Kinematic Parameters ◽  
Triceps Brachii ◽  
Manual Wheelchair ◽  
Total Mechanical Energy ◽  
Biomechanical Parameters

Purpose: The main purpose of the research conducted was the analysis of kinematic and biomechanical parameters measured during manual wheelchair ramp-climbing with the use of the anti-rollback system and the comparison of the values tested with the manual wheelchair climbing the same ramp but without any modifications. The paper presents a quantitative assessment relating to the qualitative research of the anti-rollback system performed by another research team. Method and materials: The article presents the measurement results of the wheelchair motion kinematics and the activity of four upper limb muscles for eight subjects climbing a 4.58° ramp. Each subject propelled the wheelchair both with and without the anti-rollback system. The kinematic parameters were measured by means of two incremental encoders with the resolution of 500 impulses per single revolution of the measurement wheel. Whereas, the muscle activity was measured by means of surface electromyography with the use of Noraxon Mini DTS apparatus equipped with four measurement channels. Results: The surface electromyography measurement indicated an increase in the muscle activity for all four muscles, during the use of the anti-rollback system. The increase was: 18.56% for deltoid muscle anterior, 12.37% for deltoid muscle posteriori, 13.0% for triceps brachii, and 15.44% for extensor carpi radialis longus. As far as the kinematics analysis is concerned, a decrease in the measured kinematic parameters was observed in most participants. The medium velocity of the propelling cycle decreased by 26%. The ratio of the generated power and the loss power in a single propelling cycle λ had decreased by 18%. The least decrease was recorded for the measurement of mechanical energy E and the propelling cycle duration time. For the total mechanical energy, the decrease level was 3%, and for the propelling cycle duration it was 1%. The research carried out did not demonstrate any impact of the anti-rollback system use on the push phase share in the entire propelling cycle.

scholarly journals Selective Activation of the Infraspinatus Muscle

2013 ◽  
Vol 48 (3) ◽  
pp. 346-352 ◽  
Author(s):  
Sung-Min Ha ◽  
Oh-Yun Kwon ◽  
Heon-Seock Cynn ◽  
Won-Hwee Lee ◽  
Su-Jung Kim ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Repeated Measures ◽  
External Rotation ◽  
Trapezius Muscle ◽  
Deltoid Muscle ◽  
Limited Information ◽  
Cross Sectional ◽  
Bonferroni Adjustment ◽  
Infraspinatus Muscle ◽  
Shoulder External Rotation

Context: To improve selective infraspinatus muscle strength and endurance, researchers have recommended selective shoulder external-rotation exercise during rehabilitation or athletic conditioning programs. Although selective strengthening of the infraspinatus muscle is recommended for therapy and training, limited information is available to help clinicians design a selective strengthening program. Objective: To determine the most effective of 4 shoulder external-rotation exercises for selectively stimulating infraspinatus muscle activity while minimizing the use of the middle trapezius and posterior deltoid muscles. Design: Cross-sectional study. Setting: University research laboratory. Patients or Other Participants: A total of 30 healthy participants (24 men, 6 women; age = 22.6 ± 1.7 years, height = 176.2 ± 4.5 cm, mass = 65.6 ± 7.4 kg) from a university population. Intervention(s): The participants were instructed to perform 4 exercises: (1) prone horizontal abduction with external rotation (PER), (2) side-lying wiper exercise (SWE), (3) side-lying external rotation (SER), and (4) standing external-rotation exercise (STER). Main Outcome Measure(s): Surface electromyography signals were recorded from the infraspinatus, middle trapezius, and posterior deltoid muscles. Differences among the exercise positions were tested using a 1-way repeated-measures analysis of variance with Bonferroni adjustment. Results: The infraspinatus muscle activity was greater in the SWE (55.98% ± 18.79%) than in the PER (46.14% ± 15.65%), SER (43.38% ± 22.26%), and STER (26.11% ± 15.00%) (F3,87 = 19.97, P &lt; .001). Furthermore, the SWE elicited the least amount of activity in the middle trapezius muscle (F3,87 = 20.15, P &lt; .001). Posterior deltoid muscle activity was similar in the SWE and SER but less than that measured in the PER and STER (F3,87 = 25.10, P &lt; .001). Conclusions: The SWE was superior to the PER, SER, and STER in maximizing infraspinatus activity with the least amount of middle trapezius and posterior deltoid activity. These findings may help clinicians design effective exercise programs.

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