Recruitment of the Thigh Muscles During Sprint Cycling by Muscle Functional Magnetic Resonance Imaging

Akima, Hiroshi; Kinugasa, Ryuta; Kuno, Shinya

doi:10.1055/s-2004-821000

Cited by 69 publications

(77 citation statements)

References 28 publications

(56 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…1 H-magnetic resonance (MR) imaging can be used to estimate the activity of superˆcial and deep muscles, and MR imaging can document changes produced by exercise in human muscle tissue. [1][2][3][4][5][6][7][8] In contrast to non-exercising tissues, muscles used during exercise appear hyperintense, and this hyperintensity declines during recovery. Exercised-induced changes in signal primarily result from increases in the transverse relaxation time (T 2 ) of tissue caused by changes in water content and are most pronounced on T 2 -weighted images.…”

Section: Introductionmentioning

confidence: 99%

T2 Mapping of Muscle Activity using Ultrafast Imaging

et al. 2011

View full text Add to dashboard Cite

Measuring exercise-induced muscle activity is essential in sports medicine. Previous studies proposed measuring transverse relaxation time (T 2 ) using muscle functional magnetic resonance imaging (mfMRI) to map muscle activity. However, mfMRI uses a spin-echo (SE) sequence that requires several minutes for acquisition. We evaluated the feasibility of T 2 mapping of muscle activity using ultrafast imaging, called fast-acquired mfMRI (fastmfMRI), to reduce image acquisition time. The current method uses 2 pulse sequences, spin-echo echo-planar imaging (SE-EPI) and true fast imaging with steady precession (TrueFISP). SE-EPI images are used to calculate T 2 , and TrueFISP images are used to obtain morphological information. The functional image is produced by subtracting the image of muscle activity obtained using T 2 at rest from that produced after exercise. Final fast-mfMRI images are produced by fusing the functional images with the morphologic images. Ten subjects repeated ankle plantar ‰exion 200 times. In the fused images, the areas of activated muscle in the fast-mfMRI and SE-EPI images were identical. The geometric location of the fast-mfMRI did not diŠer between the morphologic and functional images. Morphological and functional information from fast-mfMRI can be applied to the human trunk, which requires limited scan duration. The diŠerence obtained by subtracting T 2 at rest from T 2 after exercise can be used as a functional image of muscle activity.

show abstract

Section: Introductionmentioning

confidence: 99%

T2 Mapping of Muscle Activity using Ultrafast Imaging

et al. 2011

View full text Add to dashboard Cite

show abstract

“…For example, Akima et al (2005) showed that activation pattern of the adductor magnus (AM) muscle resembled that of the knee extensors, and that an index of activation, i.e., change in T2 time, of AM muscle was highly correlated with power output during sprint cycling (r = 0.688, p < 0.0001) (Akima et al 2005). Richardson et al (1998) and Endo et al (2007) also reported that activation pattern of AM muscle did not diVer from those of the knee extensors and Xexors during moderate to very heavy pedaling exercise.…”

Section: Introductionmentioning

confidence: 99%

Electromyographic analysis of hip adductor muscles during incremental fatiguing pedaling exercise

et al. 2009

View full text Add to dashboard Cite

The purpose of this study was to investigate activity of hip adductor muscles over time and during a representative crank cycle in fatiguing pedaling. Sixteen healthy men performed incremental pedaling exercise until exhaustion. During the exercise, surface electromyogram (EMG) was detected from adductor magnus (AM), adductor longus (AL), and selected thigh muscles. Temporal changes to normalized EMG in AM muscle resembled those in vastus lateralis (VL) muscle, whereas those in AL muscle showed later onset of increase from baseline compared with AM and VL muscles. During a representative crank cycle, the same level of normalized EMG was found between propulsive and pulling phases for AM muscle, whereas muscle activation of AL muscle during the pulling phase was statistically significant higher than that during the propulsive phase. We concluded that AM and AL muscles were gradually recruited over time during fatiguing pedaling exercise, but their temporal change and activation phases were not completely the same.

show abstract

“…Recent muscle-functional magnetic-resonance-imaging data showed that vastus lateralis and vastus medialis volume accounted for 70% of the variance in measured maximal power during repeated 6-second sprints. 15 Similarly, lean thigh volume (r 2 = .86) 1 and lower limb volume (r = .92) 16 have been reported to be highly predictive of maximal power. Clearly, increased muscle mass will increase the power produced by a muscle of any specifi c fi ber-type distribution.…”

mentioning

confidence: 96%

Understanding Sprint-Cycling Performance: The Integration of Muscle Power, Resistance, and Modeling

Martin

Davidson

Pardyjak³

2007

International Journal of Sports Physiology and Performance

View full text Add to dashboard Cite

Sprint-cycling performance is paramount to competitive success in over half the world-championship and Olympic races in the sport of cycling. This review examines the current knowledge behind the interaction of propulsive and resistive forces that determine sprint performance. Because of recent innovation in fi eld power-measuring devices, actual data from both elite track-and road-cycling sprint performances provide additional insight into key performance determinants and allow for the construction of complex models of sprint-cycling performance suitable for forward integration. Modeling of various strategic scenarios using a variety of fi eld and laboratory data can highlight the relative value for certain tactically driven choices during competition.Key Words: exercise performance, physical performance, sport, sport physiology, biomechanics, anaerobicOf the 28 world-championship races governed by the Union Cycliste Internationale (UCI), 8 are all-out sprint events (menʼs and womenʼs sprint, 500/1000-m time trial, Keirin, and BMX), 4 are often decided in the fi nishing sprint (menʼs and womenʼs road race and scratch race), and 2 require repeated sprints (menʼs and womenʼs points race). Thus, sprint performance is a major determinant of most world-championship racing events. Ultimately, sprint performance represents equilibrium of propulsive power and resistance. In this article, we will review factors that infl uence maximal cycling power and cycling resistance and the limited investigations exploring sprint-bicycling performance. Sprint-performance articles are quite limited because devices that accurately quantify power during actual bicycling have only recently been developed and validated. Finally, we will integrate aspects of muscle power and resistance in the context of sprint performance.

show abstract

Recruitment of the Thigh Muscles During Sprint Cycling by Muscle Functional Magnetic Resonance Imaging

Cited by 69 publications

References 28 publications

T2 Mapping of Muscle Activity using Ultrafast Imaging

T2 Mapping of Muscle Activity using Ultrafast Imaging

Electromyographic analysis of hip adductor muscles during incremental fatiguing pedaling exercise

Understanding Sprint-Cycling Performance: The Integration of Muscle Power, Resistance, and Modeling

Contact Info

Product

Resources

About