Eline De Ridder

The influence of dry needling of the trapezius muscle on muscle blood flow and oxygenation

OBJECTIVE The purpose of this study was to investigate the effect of dry needling on the blood flow and oxygen saturation of the trapezius muscle. METHODS Twenty healthy participants participated in this study. One single dry needling procedure was performed in the right upper trapezius, at a point located midway between the acromion edge and the seventh cervical vertebrae. Using the oxygen to see device, blood flow and oxygen saturation were evaluated at the treated point and 3 distant points (similar point in the left upper trapezius and 30 mm laterally from this midpoint). Measurements were taken at baseline and in the recovery period (0, 5, and 15 minutes posttreatment). RESULTS After removal of the needle, the blood flow and oxygen saturation increased significantly from the pretreatment level in the treated point (P ≤ .001), and these values remained high throughout the 15-minute recovery period. There were only minor changes in the distant points. CONCLUSIONS These results suggest that dry needling enhances the blood flow in the stimulated region of the trapezius muscle but not in a distant region used in this study.

Trunk extension exercises: How is trunk extensor muscle recruitment related to the exercise dosage?

Trunk extension exercises are used to train endurance and strength of the trunk extensor muscles. Appropriate exercise dosage is crucial to achieve specific training effects, however literature describing the relation between the predetermined exercise intensity and the actual trunk extensors activity is scarce and inconclusive. To examine whether the actual activity of the thoracic and lumbar extensors during extensions exercises correspond with the predetermined intensity, electromyographic evaluation of the trunk extensors was performed during trunk extension exercises at various intensities expressed as percentages of 1-RM. The 1-RM was predetermined using 2 different methods: (1) through direct estimation by determining the maximum isometric force produced during semi-seated trunk extension on a Tergumed rehabilitation device, (2) through indirect estimation calculated based on the relation between the maximum number of repetitions of trunk extension from prone lying on a variable angle chair and the submaximal resistance at which the repetitions were performed as presented on the Holten-diagram. The total trunk muscle activity during extension exercises performed semi-seated on a rehabilitation device or from prone lying corresponds with the predetermined dosage using both estimation methods. The indirect estimation method more accurately predicts the actual trunk extensor activity for low load training than for high load training. However, the direct estimation method is suitable to closely predetermine the load and actual trunk extensors activity during high load exercises. A shift from a differential recruitment between the thoracic and lumbar extensors at low intensities to a more homogenous recruitment at high intensities is observed during semi-seated trunk extension exercises. During prone extension exercises both muscle groups equally contribute to the total muscle work regardless of the exercise intensity. Based on these findings suggestions regarding the appropriate choice of estimation and performance method are made.

Applying an active lumbopelvic control strategy during lumbar extension exercises: Effect on muscle recruitment patterns of the lumbopelvic region

OBJECTIVE Examine whether implementing an active lumbopelvic control strategy during high load prone lumbar extension exercises affects posterior extensor chain recruitment and lumbopelvic kinematics. METHODS Thirteen healthy adults acquired an optimal active lumbopelvic control strategy during guided/home-based training sessions. During the experimental session electromyography was used to evaluate the activity of the posterior extensor chain muscles during high load trunk/bilateral leg extension exercises with/without application of the strategy. Video-analysis was used to evaluate thoracic/lumbar/hip angles. RESULTS Implementing the active lumbopelvic control strategy decreased the lordotic angle during trunk (p=0.045; -3.2°) and leg extension exercises (p=0.019; -10°). The hip angle was solely affected during trunk extension (p<0.001;+9.2°). The posterior extensor chain (i.e. mean of the relative activity of all muscles (%MVIC) was recruited to a higher extent (p=0.026;+9%) during trunk extension exercises performed with active lumbopelvic control. Applying the strategy during leg extension exercises lead to less activity of longissimus thoracic (p=0.015; -10.2%) and latissimus dorsi (p=0.010; -4.4%), and increased gluteus maximus activity (p≤0.001;+16.8%). CONCLUSIONS When healthy people are taught/instructed to apply an active lumbopelvic control strategy, this will decrease the degree of lumbar (hyper)lordosis and this influences the recruitment patterns of trunk and hip extensors. Hence, the possible impact on predetermined training goals should be taken into account by trainers.