Consequences of Repetitive Toenail Cutting by Podiatric Physicians on Force Production, Endurance to Fatigue, and the Electromyogram of the Flexor Digitorum Superficialis Muscles

2014 ◽  
Vol 104 (5) ◽  
pp. 486-492 ◽  
Author(s):  
Bruno Vie ◽  
Remy Loffredo ◽  
Farid Sanahdji ◽  
Jean-Paul Weber ◽  
Yves Jammes
Keyword(s):  
Power Spectra ◽  
Force Production ◽  
Median Frequency ◽  
Mean Square ◽  
Flexor Digitorum Superficialis ◽  
Isometric Handgrip ◽  
Time Index ◽  
Tension Time ◽  
Post Tetanic Potentiation ◽  
Flexor Digitorum

Background We hypothesized that the repetitive use of a toenail clipper by podiatric physicians could induce fatigue of the flexor digitorum superficialis (FDS) muscle, reducing the accuracy of toenail cutting. Methods We examined the consequences of cutting a plastic sheet, reproducing the resistance of thick toenails, with a podiatric medical clipper on the maximal handgrip force (Fmax) developed by the FDS muscle and an isometric handgrip sustained at 50% of Fmax, during which endurance to fatigue and changes in the power spectra of the surface FDS muscle electromyogram (root mean square and median frequency) were measured. The same participants randomly performed one or five runs of 30 successive cuttings, each on different days. Results After the first and fifth cutting runs, Fmax increased, suggesting a post-tetanic potentiation. During the handgrip sustained at 50% of Fmax, we measured a significant reduction in the tension-time index after the first cutting run. Moreover, after the fifth cutting run, the tension-time index decrease was significantly accentuated, and the decrease in FDS muscle median frequency was enhanced. No median frequency decline was measured during the cutting runs. Conclusions These results suggest that the efficacy of occupational podiatric medical tasks progressively declines with the repetition of toenail cutting. We propose solutions to remedy this situation.

scholarly journals Recovery and Fatigue Behavior of Forearm Muscles during a Repetitive Power Grip Gesture in Racing Motorcycle Riders

2021 ◽  
Vol 18 (15) ◽  
pp. 7926
Author(s):  
Michel Marina ◽  
Priscila Torrado ◽  
Raul Bescós
Keyword(s):  
Duty Cycle ◽  
Fatigue Behavior ◽  
Median Frequency ◽  
Flexor Digitorum Superficialis ◽  
Muscle Training ◽  
Maximal Voluntary Isometric Contraction ◽  
Power Grip ◽  
Road Racing ◽  
Flexor Digitorum ◽  
Forearm Muscle

Despite a reduction in the maximal voluntary isometric contraction (MVCisom) observed systematically in intermittent fatigue protocols (IFP), decrements of the median frequency, assessed by surface electromyography (sEMG), has not been consistently verified. This study aimed to determine whether recovery periods of 60 s were too long to induce a reduction in the normalized median frequency (MFEMG) of the flexor digitorum superficialis and carpi radialis muscles. Twenty-one road racing motorcycle riders performed an IFP that simulated the posture and braking gesture on a motorcycle. The MVCisom was reduced by 53% (p < 0.001). A positive and significant relationship (p < 0.005) was found between MFEMG and duration of the fatiguing task when 5 s contractions at 30% MVCisom were interspersed by 5 s recovery in both muscles. In contrast, no relationship was found (p > 0.133) when 10 s contractions at 50% MVC were interspersed by 1 min recovery. Comparative analysis of variance (ANOVA) confirmed a decrement of MFEMG in the IFP at 30% MVCisom including short recovery periods with a duty cycle of 100% (5 s/5 s = 1), whereas no differences were observed in the IFP at 50% MVCisom and longer recovery periods, with a duty cycle of 16%. These findings show that recovery periods during IFP are more relevant than the intensity of MVCisom. Thus, we recommend the use of short recovery periods between 5 and 10 s after submaximal muscle contractions for specific forearm muscle training and testing purposes in motorcycle riders.

scholarly journals Bioenergetics of contracting skeletal muscle after partial reduction of blood flow

1998 ◽  
Vol 84 (6) ◽  
pp. 1882-1888 ◽  
Author(s):  
Michael C. Hogan ◽  
L. Bruce Gladden ◽  
Bruno Grassi ◽  
Creed M. Stary ◽  
Michele Samaja
Keyword(s):  
Blood Flow ◽  
Steady State ◽  
Force Production ◽  
Normal Blood ◽  
Normal Flow ◽  
Contracting Muscle ◽  
Time Index ◽  
Atp Concentration ◽  
Tension Time ◽  
Normal Blood Flow

The purpose of this study was to examine the bioenergetics and regulation of O2 uptake (V˙o 2) and force production in contracting muscle when blood flow was moderately reduced during a steady-state contractile period. Canine gastrocnemius muscle ( n = 5) was isolated, and 3-min stimulation periods of isometric, tetanic contractions were elicited sequentially at rates of 0.25, 0.33, and 0.5 contractions/s (Hz) immediately followed by a reduction of blood flow [ischemic (I) condition] to 46 ± 3% of the value obtained at 0.5 Hz with normal blood flow. TheV˙o 2 of the contracting muscle was significantly ( P < 0.05) reduced during the I condition [6.5 ± 0.8 (SE) ml ⋅ 100 g−1 ⋅ min−1] compared with the same stimulation frequency with normal flow (11.2 ± 1.5 ml ⋅ 100 g−1 ⋅ min−1), as was the tension-time index (79 ± 12 vs. 123 ± 22 N ⋅ g−1 ⋅ min−1, respectively). The ratio ofV˙o 2 to tension-time index remained constant throughout all contraction periods. Muscle phosphocreatine concentration, ATP concentration, and lactate efflux were not significantly different during the I condition compared with the 0.5-Hz condition with normal blood flow. However, at comparable rates of V˙o 2 and tension-time index, muscle phosphocreatine concentration and ATP concentration were significantly less during the I condition compared with normal-flow conditions. These results demonstrate that, in this highly oxidative muscle, the normal balance of O2 supply to force output was maintained during moderate ischemia by downregulation of force production. In addition, 1) the minimal disruption in intracellular homeostasis after the initiation of ischemia was likely a result of steady-state metabolic conditions having already been activated, and 2) the difference in intracellular conditions at comparable rates ofV˙o 2 and tension-time index between the normal flow and I condition may have been due to altered intracellular O2 tension.

scholarly journals Advanced Rock Climbers Exhibit Greater Finger Force and Resistance to Fatigue Compared to Novices During Treadwall Climbing

2020 ◽  
Author(s):  
Philip F. Ferrara ◽  
James Becker ◽  
John G. Seifert
Keyword(s):  
Muscle Activity ◽  
Force Plate ◽  
Force Production ◽  
Median Frequency ◽  
Finger Force ◽  
Flexor Muscle ◽  
Significant Group ◽  
Maximum Voluntary Isometric Contraction ◽  
Before And After ◽  
Flexor Digitorum

AbstractBackgroundThe purpose of the study was to investigate the effects of rock climbing experience on time to fatigue (TTF), finger flexor force production relative to body weight (REL FP), and changes in finger flexor muscle activity during tread wall climbing.MethodsEight advanced and seven novice sport rock climbers performed a climbing protocol on a treadwall system. The protocol consisted of climbing for six 5-minute intervals or until voluntary failure. A mounted force plate was used to measure finger force production before and after the climbing protocol. Subjects performed a 20-second maximum voluntary isometric contraction (MVIC) against the force plate with the dominant and non-dominant fingertips in a common climbing hand configuration known as a half crimp. Muscle activity was monitored with electromyographic electrodes placed bilaterally over the subject’s flexor digitorum superficialis. Median frequency (MF) and root mean square (RMS) were analyzed. The treadwall was set at a difficulty of 9 IRCRA/5.9 YDS. It rotated at 7 m/min and was fixed at 7° overhanging.ResultsSignificant group differences were observed in subject characteristics, TTF (30±0 vs. 25.7±3.6 min), REL FP (5.6±1.2 vs. 3.2±0.9 N/kg BW), ΔFP (+1.5±12.3% vs. -31±16%), and ΔMF (+6.3±22.4% vs. -17.6±10.9%).ConclusionThe results of this study demonstrate that advanced climbers possess greater finger flexor force production and resistance to fatigue compared to novices during bouts of climbing on a treadwall system. This may be attributed to physiological changes due to years of training, such as metabolic adaptations and oxygenation capacity in the forearm musculature.

The anatomy and function of a bilateral accessory flexor digitorum superficialis muscle: A case report and review of literature

Morphologie ◽  
2020 ◽  
Vol 104 (347) ◽  
pp. 287-292
Author(s):  
M. Maniglio ◽  
C.E. Chalmers ◽  
G. Thürig ◽  
C. Passaplan ◽  
C. Müller ◽  
...  
Keyword(s):  
Case Report ◽  
Flexor Digitorum Superficialis ◽  
Review Of Literature ◽  
And Function ◽  
Flexor Digitorum

Reciprocal Coactivation Patterns of the Lateral and Medial Quadriceps and Hamstrings during Low- and Moderate-Speed Isokinetic Movement

1998 ◽  
Vol 7 (3) ◽  
pp. 182-196 ◽  
Author(s):  
Ronald V. Croce ◽  
John P. Miller ◽  
Robert Confessore ◽  
James C. Vailas
Keyword(s):  
Knee Joint ◽  
Female Athletes ◽  
Vastus Lateralis ◽  
Biceps Femoris ◽  
Median Frequency ◽  
Vastus Medialis ◽  
Mean Square ◽  
Joint Movement ◽  
Surface Electrodes ◽  
Emg Patterns

The purpose of this study was to examine coactivation patterns of the lateral and medial quadriceps and the lateral and medial hamstrings during low- and moderate-speed isokinetic movements. Twelve female athletes performed isokinetic knee assessments at 60 and 180°/s. Root mean square electromyographic (rmsEMG) activity and the median frequency of the EMG (mfEMG) were determined by placing bipolar surface electrodes on the vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), and medial hamstrings (MH). Results of rmsEMG indicated that the VM showed almost twice the coactivation of the VL (p< .05), and that the BF showed almost four times the coactivation of the MH (p <.05). Finally, differences were noted in the mfEMG (p< .05), with the VM displaying different recruitment patterns at 180°/s as an agonist compared to that as an antagonist. Results indicated that when acting as antagonists, the VM and BE display the greatest EMG patterns during isokinetic knee joint movement.

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