In order to relate EMG signs of localized muscle fatigue to subjectively perceived muscle fatigue, a study was undertaken on 20 healthy volunteers exposing their right trapezius muscle by raising the arm to 90 degrees of abduction. Every person performed two contractions: 0 kg hand load during 5 min and 2 kg hand load during 2.5 min. Surface EMG was recorded and analysed with respect to RMS amplitude and mean power frequency (MPF). Subjective muscle fatigue was estimated with a psychophysical rating scale (Borg's CR-10 Scale). At high load level we found a significant correlation between MPF and the CR-scores (r = -0.46), but at low load level there was no correlation. At high load level there was a linear decrease of MPF with increasing load dose, but at low load level the MPF did not change, despite significant subjective fatigue. There was a linear rise of the CR-score with increasing load dose, more pronounced at high load level. It was concluded, that at low load levels common in working life, MPF and subjective scores seem to provide different fatigue information. Moreover, the MPF did not seem to work as a valid estimator of muscle fatigue at this low load level. Caution is recommended if it is to be used in static low-load situations.

No abstract

To investigate the movement of the tibial end in the sagittal plane in the PTB prosthetic socket during a gait cycle, 7 patients with a median age of 72 years were examined using X-ray technique. The gait cycle was reduced to four different static positions: heel contact, midstance, push-off and swing phase. The mean value of tibial movement in the socket in the anteroposterior direction was 2.2 cm, in proximodistal direction 2.8 cm, and the total sagittal movement during the whole gait cycle was 7.5 cm. The results indicate that one factor affecting the magnitude of the movement was the prestretching of soft tissues. All the patients who experienced a good prosthetic fitting had their soft tissues prestretched. The extreme dorsal and proximal positions of the tibial end during the gait cycle was in the swing phase position. The extreme distal position occurred somewhere between mid-stance and push-off. The extreme anterior position of the tibial end was seen during heel contact. This study has shown the magnitude of the movements in a PTB socket during a simulated gait cycle. The study has given hints on factors affecting prosthetic fitting, and further research within this field might provide indications of how to optimise socket shape to give maximal patient comfort.

In this prospective study, the overall treatment and outcome of patients that underwent major lower limb amputation in a defined population is described. The study was performed over a five year period in the Health Care District of North-East Skåne, Sweden. Some 190 patients, permanent inhabitants of the Health Care District, underwent major lower limb amputation. Sixteen (16) of these patients had amputations before the study started and went through late second leg amputation during the period. One hundred and seventy four (174) patients had primary major amputation. Seventy nine (79) were men and 95 were women, with a median age of 81. The re-amputation rate was 17% although the primary knee preservation ratio was as high as 3.0:1. Rigid dressing was the standard method following trans-tibial amputation and was used for 5–7 days. ICEROSS∗ silicone liner was used for compression therapy in 90% of all cases that resulted in delivery of a prosthesis. Prostheses were delivered to 43% of all patients with primary amputations. These patients spent a median of 13 days at the orthopaedic clinic, 55 days at the rehabilitation unit. Pressure casting was used as a standard method in the production of the prosthetic socket. ICEX∗ carbon-fibre socket was used in 52%. New procedures, treatments and techniques were introduced, standardised and evaluated whilst the routines in the hospital were reorganised. In this way, a system has been implemented that better guarantees the outcome of the whole procedure and the service received by this category of patients.

In this study we have examined the variation of mean power frequency (MPF) in the electromyogram (EMG) from the non-fatigued trapezius muscle, with different external hand loads, in different shoulder joint positions, different torques and different planes of movement. The study was limited to the functional range of movement in the shoulder joint. It was performed on 19 healthy subjects. Surface EMG was recorded, analysed by means of a computer programme and examined by regression analysis. Normalized MPF values were calculated by dividing the MPF by the individual average MPF for all positions and loads. The results indicated no major variation in normalized MPF. The largest systematic variation of normalized MPF, +/- 8%, was related to joint angle. We have concluded that the MPF value obtained initially can be used within the functional range of movement to calculate the relative decrease in MPF as a result of muscle fatigue, and that the decrease is significant if it exceeds 8% of the initial value.