scholarly journals The Relationship between Peak Power of Isokinetic Exercise on a Step Ergometer and Muscle Activity Characteristics

2012 ◽  
Vol 27 (4) ◽  
pp. 411-415
Author(s):  
Atsushi MIZUMOTO ◽  
Hiroyuki SHIMADA ◽  
Hikaru IHIRA ◽  
Tomohiro Nomura ◽  
Taketo FURUNA ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Peak Power ◽  
Isokinetic Exercise ◽  
The Relationship

scholarly journals The Relationship between Peak Power of Isokinetic Exercise on a Step Ergometer and Physical Function of Community-dwelling Elderly

2011 ◽  
Vol 26 (1) ◽  
pp. 139-142
Author(s):  
Atsushi MIZUMOTO ◽  
Megumi SUZUKAWA ◽  
Hyuma MAKIZAKO ◽  
Takehiko DOI ◽  
Hiroyuki SHIMADA
Keyword(s):  
Physical Function ◽  
Peak Power ◽  
Community Dwelling ◽  
Isokinetic Exercise ◽  
The Relationship

5 Examination of the relationship between changes in workload and changes in loaded countermovement jump during a rugby union season

2021 ◽  
Vol 55 (16) ◽  
pp. 941.3-942
Author(s):  
Rob Strong ◽  
Daniel West ◽  
Joe Kupsarevic
Keyword(s):  
Peak Power ◽  
Rank Order ◽  
Rugby Union ◽  
Countermovement Jump ◽  
Match Play ◽  
Time To Peak ◽  
Significant Relationships ◽  
Flight Season ◽  
Acute Changes ◽  
The Relationship

BackgroundThe loaded countermovement jump (CMJ) is a variation on the normal CMJ (bodyweight-only), used routinely in sport settings as a measure of neuromuscular fatigue (NMF). Although commonplace, the CMJ variables that are most sensitive to NMF remain somewhat unclear.PurposeThe aim of this study was to examine the relationship between changes in workload and changes in the loaded CMJ; specifically, to determine its suitability for assessment of NMF.MethodsEighteen professional rugby union players performed loaded CMJ tests on seven occasions over the course of thirteen weeks, during an English top-flight season. Eight CMJ variables were measured, assessing different aspects of the CMJ. Workload was measured by GPS total distance and was the sum of the previous week’s data, recorded in on-field training and match-play. Spearman’s rank-order correlations were calculated to identify the relationship between changes in workload and changes in loaded CMJ variables.ResultsNo significant relationships were found between loaded CMJ variables and workload with no lag or workload lagged one week. Significant relationships were found between workload lagged 2 weeks and flight time/contact time (FT-CT; rs=-0.35; p=0.04) and time to peak power (TtPP; rs=0.35; p=0.05).ConclusionThis study suggests loaded CMJ is not a suitable test to monitor acute changes to NMF. However, results also indicate that FT-CT and TtPP, are associated with changes in workload lagged 2-weeks. Therefore, certain CMJ variables may prove useful to help prescribe alterations to athlete training plans following periods of heavy workload.

Spatiotemporal characteristics of 5-HT and dopamine-induced rhythmic hindlimb activity in the in vitro neonatal rat

1996 ◽  
Vol 75 (4) ◽  
pp. 1472-1482 ◽  
Author(s):  
O. Kiehn ◽  
O. Kjaerulff
Keyword(s):  
Muscle Activity ◽  
Central Pattern Generators ◽  
Rhythmic Activity ◽  
Biceps Femoris ◽  
Ventral Root ◽  
Neonatal Rat ◽  
Cycle Duration ◽  
Spatiotemporal Characteristics ◽  
The Relationship

1. Rhythmic activity was induced with either serotonin (5-HT; 10-100 microM) or dopamine (0.1-1.0 mM), in the in vitro spinal cord preparation of neonatal rats, with one intact hindlimb attached. Patterns of activity were investigated with multiple EMG recordings and the spatiotemporal characteristics of 5-HT- and dopamine-induced activity compared. 2. Dopamine-induced rhythmic activity was slow (cycle duration: 2.2-70.1 s) and irregular, whereas rhythmic activity induced by 5-HT was fast (cycle duration: 1.3-5.1 s) and regular. 3. During 5-HT- and dopamine-induced rhythmic activity, the timing of muscular activity was similar for hip flexors and hip adductors, for semimembranosus (hip extensor), and for muscles controlling the ankle and the foot. 4. In contrast, notable differences in the phase in the pattern induced by 5-HT compared with that induced by dopamine were found in the biceps femoris, semitendinosus, and quadriceps muscles. Biceps femoris and semitendinosus (functional hip extensors and knee flexors) were always extensor-like during 5-HT-induced activity, whereas in dopamine, these muscles displayed flexor-like bursts and double bursts as well as extensor-like bursts. Lack of EMG activity in biceps femoris and semitendinosus was encountered also in dopamine. In rectus femoris, vastus lateralis, and vastus medialis (main function: knee extension), the activity was dominated by flexor-like bursts in 5-HT, whereas in dopamine the activity was shifted to a predominantly extensor-like pattern. 5. The relationship between flexor and extensor burst duration and cycle duration was more variable than described for locomotor activity in adult animals. 6. The relative timing of muscle activity was stable from P0 to P4. The most important difference between rats aged 0-1 days and rats aged 2-4 days was a delayed flexor-extensor transition in older animals. 7. The complex timing of hindlimb muscle activity was relatively unchanged after transecting all dorsal roots. 8. Finally, the relationship between flexor and extensor activity and ventral root discharges was determined. It was found that the L2 ventral root burst was in phase with simple flexors while the L5 burst coincide with the extensor phase. 9. We conclude, that 5-HT and dopamine can activate spinal central pattern generators (CPGs) that already at birth are able to produce distinct patterns of motor activity. Modulatory inputs thus seems to be able to reconfigure the CPGs to produce specific motor outputs.

scholarly journals Effect of mandibular position achieved using an oral appliance on genioglossus activity in healthy adults during sleep

2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Michikazu Matsuda ◽  
Toru Ogawa ◽  
Ratri M. Sitalaksmi ◽  
Makiko Miyashita ◽  
Toshimi Ito ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Vertical Displacement ◽  
Oral Appliance ◽  
Airway Patency ◽  
Test Conditions ◽  
Obstructive Sleep ◽  
Mandibular Position ◽  
Vertical Displacements ◽  
The Relationship ◽  
Airflow Sensor

Abstract Background Oral appliances (OAs) are generally designed to displace the mandible anteriorly and downward, to increase the airway patency. The present study aimed to examine the relationship between genioglossus (GG) muscle activity and mandibular position, considering both anterior and vertical displacements during sleep. Methods Seven healthy male adults aged 29.4 ± 1.99 years were evaluated. Maxillary and mandibular OAs were fabricated from 2-mm-thick resin plates with pressure-welding. The activity of the left GG was recorded using two silver ball electrodes attached to the lingual edge of the mandibular OA. Respiratory status and right masseter muscle activity were measured by an airflow sensor and surface electrodes, respectively. Electroencephalography was used to determine the sleep status. Stage 2 (the second stage of sleep) was defined as the state of sleeping. Four test conditions with different mandibular positions (0 and 50% anterior protrusion) and bite openings (4 mm and 12 mm) were examined. Results GG activity in SL4A (4 mm bite opening, 50% protrusion during sleep) and SL12 (12 mm bite opening, 0% protrusion during sleep) were significantly higher than that in SL4 (4 mm bite opening, 0% protrusion during sleep). Respiratory volume did not significantly differ between all test conditions. Conclusion GG activity is influenced not only by anterior protrusion of the mandible but also by vertical displacement during sleep. Thus, when determining the effectiveness of intraoral appliances in the treatment of obstructive sleep apnea, both protrusion and the size of the mandibular opening should be evaluated and taken into account.

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