Muscle endurance and power spectrum of the triceps brachii in wheelchair marathon racers with paraplegia

Abstract

Objective: To investigate differences in triceps brachii endurance and electrical activity between elite marathon and recreational wheelchair athletes with paraplegia. Design and methods: Nine male elite wheelchair athletes between 20 and 46 years of age (average 29.078.2 years) with complete (ASIA-A) T4-L1 paraplegia were compared to a group of six male height-and weight-matched recreational wheelchair athletes with similar ages and injuries. Right triceps brachii maximum voluntary contraction (MVC), as well as the duration of the ability to maintain a 50% MVC were determined for all subjects. Median frequency (MF) and mean power frequency (MPF) were evaluated with fast Fourier transform spectrum analysis. MF and MPF rates of change were calculated and compared with the Student's t-test. Setting: Department of Rehabilitation Medicine, University of Occupational and Environmental Health, Japan. Results: Right triceps brachii MVCs of the marathoners (42.478.8 N m (range 33-55 N m)) and recreational athletes (41.679.3 N m (range 32-56 N m)) did not differ significantly (P ¼ 0.63). Endurance, however, did. All of the athletes, but none of the control subjects, were able to maintain a 50% MVC contraction of the right triceps brachii for 2 min (the average contraction duration in the latter group was 75.5716.2 s). MF and MPF of the triceps brachii decreased linearly in both groups, but the slopes in the marathoners (À8.974.6 (À3.8 to À16.4) and À9.774.6 (À4.0 to À17.2)%/min, respectively) were statistically less steep than those in the recreational athletes (À22.378.2 (À9.6 to À31.4) and À21.276.4 (À11.4 to À28.6)%/min, respectively). Conclusion: Elite marathoners and active wheelchair users have similar triceps brachii strength. The marathoner's triceps brachii, however, display a significantly improved endurance and a slower decline of MF and MPF with time than do those of their recreational athlete control group.

Muscle Maintenance by Volitional Contraction against Applied Electrical Stimulation

“…The choice may be arguable but seems appropriate as physiological research confirms an association between muscle fatigue and shifts in firing rates towards lower values [7,[12][13][14][15][16][17][18][19][20]. Moreover, regression analyses between the MF and MPF slopes with time were capable of detecting differential responses in the fiber types: with slow twitch fibers showing more resistance to fatigue than the fast twitch fibers [26,27].…”

“…However, studies on the muscle in the upper extremities also appear in the literature. For example, an investigation by members of this group found that the MF and MPF slopes in the triceps brachii of wheelchair marathoners displayed an improved endurance relative to wheelchair naïve ambulatory control subjects [20]. It is also significant that another recent upper extremity study [28] has revealed that the fast twitch fiber rich biceps reveals a steeper degradation in its firing frequency than the slow twitch rich triceps [21,22,26].…”

“…Evaluation of muscle fatigue: EMG power spectral frequency analysis was used to evaluate skeletal muscle endurance [12][13][14][15][16][17][18][19][20]. The median frequency (MF) and the mean power frequency (MPF)…”

Gender differences in wheelchair marathon performance – Oita International Wheelchair Marathon from 1983 to 2011

“…However, the paraplegic athletes had a high mean heart rate (~170 bpm) throughout a marathon 2. Power of the upper arms, lung vital capacity isokinetic muscle strength of the elbow extensors, muscle endurance of triceps brachii, and total push angle may all contribute to wheelchair marathon performance 3–6…”

Reliability of Power Spectral Analysis of Surface Electromyogram Recorded during Sustained Vastus Medialis Isometric Contraction in Assessment of Muscle Fatigability

“…The use of EMG power spectral analysis has demonstrated that muscle fatigue is associated with a shift in the MF toward lower values [11] [12] [13]. EMG power spectral analysis is also sometimes combined with histochemical analysis to determine muscle fiber type [14].…”