EMG patterns during running: Intra- and inter-individual variability

Rectified surface electromyographic (EMG) patterns of five healthy, young, physically-fit subjects running at 4.2 m s(-1) on a treadmill were recorded with the objective of defining a normal profile of EMG activity for running gait. This knowledge is important in understanding how the central nervous system (CNS) controls simple running tasks under normal conditions. The EMG signals from seven muscles (erector spinae, rectus femoris, vastus medialis, vastus lateralis, biceps femoris, tibialis anterior and gastrocnemius) were recorded, together with footswitch signals. The intra- and inter-individual variability of each muscle's EMG profile and peak times were analysed. Interindividual EMG peak time values were analysed to define the timing of the activity of the muscles studied relative to the stride cycle and its subphases. For each muscle, little variation was found within individuals in EMG profile and peak time across trials, but differences between subjects were significant (P < 0.01). EMG peak time analysis showed two distinct activation sequences of different muscles: the first at stance phase and the second at terminal swing. In conclusion, in spite of a significant variability among subjects in EMG profile and peak time values for each muscle, the EMG peak timing analysis showed a sequence of activation at stance phase, no EMG peak activity during the first double swing and another sequence of activation during terminal swing. These findings are evidence of a neuromuscular control strategy common to all subjects.

Detachable snare versus epinephrine injection in the prevention of postpolypectomy bleeding: a randomized and controlled study

BACKGROUND AND STUDY AIMS

Several endoscopic techniques have been developed to prevent bleeding after the removal of large pedunculated polyps.

PATIENTS AND METHODS

From January 1995 to December 2002, 488 consecutive patients with pedunculated colorectal polyps, the heads of which were larger than 10 mm in diameter, were randomly assigned to three groups. In group A (163 patients), detachable snares were placed at the base of the stalk and standard snares were then used for polypectomy. In group B (161 patients), the polyp stalk was injected with a 0.01 % epinephrine solution before conventional snare polypectomy. Group C (a control group including 164 patients) underwent conventional snare polypectomy without preventive measures. Early (< 24 h) and late (> 24 h - 30 days) bleeding complications were assessed. Each group was divided into two subgroups relative to the polyp size (polyps 1.0 - 1.9 cm and polyps > or = 2 cm).

RESULTS

Overall bleeding complications occurred after 4.3 % of the polypectomies. Bleeding was successfully controlled in all patients, and no blood transfusions were required. There were three cases of bleeding in group A (1.8 %), five in group B (3.1 %), and 13 in group C (7.9 %). Early bleeding was more frequent than late bleeding (15 vs. six patients). In polyps > or = 2 cm (207 patients), postpolypectomy bleeding occurred in 14 patients (6.7 %): two (2.7 %) in the detachable snare group, two (2.9 %) in the epinephrine injection group, and 10 (15.1 %) in the control group.

CONCLUSIONS

These results show that polypectomy of large pedunculated polyps is associated with a higher incidence of bleeding. Particularly in polyps larger than 2 cm, preventive measures can significantly reduce bleeding complications after polypectomy. This can be achieved with similar efficacy either by placing Endoloops or by injecting epinephrine.

The influence of high blood levels of urea on the presence of Campylobacter pylori in the stomach: a clinical study

In order to determine whether urea influences the presence of Campylobacter pylori (Cp) in the stomach, the incidence of this infection was determined in patients with chronic renal failure who received no treatment (group A) or underwent regular hemodialysis (group B). A third group was examined as control. Biopsies from the gastric antrum were taken for histological investigation and for Cp detection. No significant differences among the 3 groups of patients were found with regards to the incidence of Campylobacter pylori. Urea can be considered as a preferred metabolite but no proof that high levels influence the occurrence of the organism in the stomach was found.