Acute Muscular Responses to Practical Low-Load Blood Flow Restriction Exercise Versus Traditional Low-Load Blood Flow Restriction and High-/Low-Load Exercise.

CONTEXT: Blood flow restriction (BFR) increases muscle size and strength when combined with low loads, but various methods are used to produce this stimulus. It is unclear how using elastic knee wraps can impact acute muscular responses compared with using nylon cuffs, where the pressure can be standardized. OBJECTIVE: Investigate how elastic knee wraps compare with nylon cuffs and high-load (HL)/low-load (LL) resistance exercise. DESIGN: A randomized cross-over experimental design using 6 conditions combined with unilateral knee extension. SETTING: Human Performance Laboratory. PARTICIPANTS: A total of 9 healthy participants (males = 7 and females = 2) and had an average age of 22 (4) years. INTERVENTION: LL (30% of 1-repetition maximum [1-RM]), HL (70% 1-RM), BFR at 40% of arterial occlusion pressure (BFR-LOW), BFR at 80% of arterial occlusion pressure (BFR-HIGH), elastic knee wraps stretched by 2 in (PRACTICAL-LOW), and elastic knee wraps stretched to a new length equivalent to 85% of thigh circumference (PRACTICAL-HIGH). BFR and practical conditions used 30% 1-RM. MAIN OUTCOME MEASURES: Muscle thickness, maximum voluntary isometric contraction, and electromyography amplitude. Bayesian statistics evaluated differences in changes between conditions using the Bayes factor (BF10), and median and 95% credible intervals were reported from the posterior distribution. RESULTS: Total repetitions completed were greater for BFR-LOW versus PRACTICAL-HIGH (BF10 = 3.2, 48.6 vs 44 repetitions) and greater for PRACTICAL-LOW versus BFR-HIGH (BF10 = 717, 51.8 vs 36.3 repetitions). Greater decreases in changes in maximum voluntary isometric contraction were found in PRACTICAL-HIGH versus HL (BF10 = 1035, ∼103 N) and LL (BF10 = 45, ∼66 N). No differences in changes in muscle thickness were found between LL versus PRACTICAL-LOW/PRACTICAL-HIGH conditions (BF10 = 0.32). Greater changes in electromyography amplitude were also found for BFR-LOW versus PRACTICAL-HIGH condition (BF10 = 6.13, ∼12%), but no differences were noted between the other BFR conditions. CONCLUSIONS: Overall, elastic knee wraps produce a more fatiguing stimulus than LL or HL conditions and might be used as an alternative to pneumatic cuffs that are traditionally used for BFR exercise.

Penetrating cactus spine injury to the mediastinum of a child.

Injuries from contact with cactus plants are not uncommon in the southwestern United States and other arid landscapes. Most often, accidental encounters with sharp spines and barbs result in little more than mechanical damage to the skin and soft tissues with minor pain and irritation. Although cactus spine penetration into the skin has been reported to be a stimulus for cutaneous granuloma formation, our review of the published literature did not reveal any potentially life-threatening injuries from such insults. We present a unique case of a penetrating cactus spine to the anterior mediastinum in a child which required surgical extraction.

Laser Doppler imaging of burn scars: a comparison of wavelength and scanning methods.

UNLABELLED: Laser Doppler perfusion imaging (LDI) is a useful tool for the early clinical assessment of burn depth and prognostic evaluation of injuries that may require skin grafting. We have evaluated two commercially available laser Doppler imagers for the perfusion measurement of normal and burn scar tissue. METHODS: A single wavelength (635 nm), step-wise scanning LDI and a dual wavelength (633 and 780 nm), continuous scanning LDI were used. Twenty patients with hypertrophic burn scars (time since injury: 1 month-8 years) were recruited and the color and elevation of the scar was clinically assessed using a modified Vancouver Burn Scar Scale. Perfusion of each scar region was measured using both imagers. A symmetric contralateral region of unburned skin was also imaged to record baseline perfusion. RESULTS: Comparisons of wavelength and scanning technique were made using perfusion values obtained from 22 burn scars. Highly significant positive correlation was observed in all comparisons. In addition, output from both instruments was strongly and significantly correlated with the clinical grading of the scar. SIGNIFICANCE: Both LDI scanners perform similar perfusion measurements. The results also indicate that red and near-infrared (NIR) wavelength photons provide similar blood flow information. The faster, continuous scanning method provides a clinical advantage without a significant loss of blood flow information. However, a critical evaluation of both instruments suggests that caution must be exercised when using these optical diagnostic techniques and that some knowledge of light-tissue interaction is required for the proper analysis and interpretation of clinical data.