This study identifies the error inherent in measurement that is independent of patient factors and due to the smartphone, the installed apps, and examiner skill. Less than 2° of measurement variability was attributable to those factors alone. The data suggest that 3 smartphones with the 2 installed apps are a viable substitute for using a UG or an inclinometer when measuring angular changes that typically occur when examining ROM and demonstrate the capacity of multiple examiners to accurately use smartphone-based goniometers.

Muscle soreness, a familiar phenomenon to most athletes, has been differentiated into “acute” and “delayed onset.” The etiology of acute muscle soreness has been attributed to ischemia and the accumulation of metabolic by-products. However, the etiology of delayed onset muscle soreness (DOMS) is not so clear. Six theories have been proposed: lactic acid, muscle spasm, torn tissue, connective tissue, enzyme efflux, and tissue fluid theories. The treatment of DOMS has also been investigated. Studies in which anti-inflammatory medications have been administered have yielded varying results based on the dosage and the time of administration. Submaximal concentric exercise may alleviate soreness but does not restore muscle function. Neither cryotherapy nor stretching abates the symptoms of DOMS. Transcutaneous electrical stimulation has been shown to decrease soreness and increase range of motion, but the effect on the recovery of muscle function is unknown. Therefore, the treatment of DOMS remains an enigma.

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Background:Patterned electrical neuromuscular stimulation (PENS) uses the electrical stimulation of sensory and motor nerves to achieve a skeletal muscle contraction using an electromyogram-derived functional pattern. PENS is used extensively for neuromuscular reeducation and treatment of muscle disuse atrophy.Purpose:To explore the effectiveness of PENS as applied to the quadriceps muscles on the vertical jump of an athletic population.Study Design:Experimental with control and repeated measures over time.Methods:Healthy college athletes (54 women, 75 men) were divided into 3 groups (control, n = 30; jump, n = 33; and jump with PENS, n = 63). There was no difference among groups’ height and weight. Athletes performed a baseline standing vertical jump using a vertical jump system. The control group continued its normal daily activities with no jumping tasks included. The jump groups performed 3 sets of 12 repetitions with a 2-minute rest between sets at a frequency of 3 times per week. The PENS group did the jumping with the coordination of an electrical stimulation system. Vertical jump was retested after 6 weeks of intervention and 2 weeks after cessation.Results:A 3-way repeated measures analysis of variance for time (control, jump alone, jump with PENS) revealed a significant difference (P < 0.05) for time and an interaction between time and treatment, as well as a significant difference for the PENS group from baseline to posttest and for the jump group from posttest to follow-up jump. There was no significant difference between groups for the baseline vertical jump.Conclusions:This study demonstrated that 6 weeks of vertical jump training coordinated with PENS resulted in a greater increase than jumping only or control. This pattern of stimulation with PENS in combination with jump training may positively affect jumping.