Preoperative Physical Activity Predicts Surgical Outcomes Following Lung Cancer Resection.

OBJECTIVES: To assess whether preoperative levels of physical activity predict the incidence of post-operative complications following anatomical lung resection. METHODS: Levels of physical activity (daily steps) were measured for 15 consecutive days using pedometers in 90 consecutive patients (prior to admission). Outcomes measured were cardiac and respiratory complications, length of stay, and 30-day re-admission rate. RESULTS: A total of 78 patients' datasets were analysed (12 patients were excluded due to non-compliance). Based on steps performed they were divided into quartiles; 1 (low physical activity) to 4 (high physical activity). There were no significant differences in age, smoking history, COPD, BMI, percentage predicted FEV1 and KCO and cardiovascular risk factors between the groups. There were significantly fewer total complications in quartiles 3 and 4 (high physical activity) compared to quartiles 1 and 2 (low physical activity) (8 vs 22; P = .01). There was a trend (P > .05) towards shorter hospital length of stay in quartiles 3 and 4 (median values of 4 and 5 days, respectively) compared to quartiles 1 and 2 (6 days for both groups). CONCLUSIONS: Preoperative physical activity can help to predict postoperative outcome and can be used to stratify risk of postoperative complications and to monitor impact of preoperative interventions, ultimately improving short term outcomes.

Contralateral effect of short-duration unilateral neuromuscular electrical stimulation and focal vibration in healthy subjects.

BACKGROUND: The "contralateral effect" phenomenon refers to the strength gain in the opposite, untrained homonymous muscle following unilateral training. Previous studies showed that neuromuscular electrical stimulation (NMES) of the right quadriceps facilitated maximal voluntary strength and efferent neural drive of the left knee extensors, while no previous study investigated the contralateral effect elicited by focal muscle vibration. AIM: The aim of this study was to investigate whether quadriceps NMES and focal vibration, when applied unilaterally, have the same potential to enhance the contralateral muscle strength and the associated neural drive. DESIGN: Randomized controlled experimental study. SETTING: University laboratory. POPULATION: Healthy subjects. METHODS: Subjects completed several maximal voluntary contractions (MVCs) of the left quadriceps (tested muscle) while the right quadriceps (treated muscle) received no conditioning stimulation (control condition), NMES or focal vibration. Paired supramaximal stimuli were delivered to the left quadriceps during and immediately after the MVCs to assess voluntary activation. The EMG activity of vastus lateralis, vastus medialis, and rectus femoris muscles of the left quadriceps was also concomitantly recorded. RESULTS: MVC torque and voluntary activation of the left quadriceps increased during contralateral NMES and vibration. A remarkable inter-individual variability was observed in the contralateral effect of NMES and vibration. In fact, MVC and voluntary activation increases were particularly evident in subjects "responders" to both treatments (who showed NMES-elicited increases in MVC and voluntary activation of 22.5% and 15.8%, respectively, and vibration-elicited increases of 13.1% and 10.7%, respectively). Moreover, we found that the increases in voluntary activation and EMG activity elicited by NMES were higher than those elicited by focal vibration. We also found that voluntary activation increases were higher in subjects presenting lower baseline levels of voluntary activation. CONCLUSIONS: The short-duration unilateral application of quadriceps NMES and focal vibration increased MVC torque and efferent neural drive of the contralateral homologous muscle in healthy subjects. CLINICAL REHABILITATION IMPACT: As the two physical therapy modalities can be useful to maximize motor unit recruitment contralaterally to the side of application, they could be incorporated in rehabilitation protocols when unilateral voluntary contractions are uncomfortable, painful or not feasible.

Clinical Use of Neuromuscular Electrical Stimulation for Neuromuscular Rehabilitation: What Are We Overlooking?

The clinical success of neuromuscular electrical stimulation (NMES) for neuromuscular rehabilitation is greatly compromised by the poor consideration of different physiological and methodological issues that are not always obvious to the clinicians. Therefore, the aim of this narrative review is to reexamine some of these fundamental aspects of NMES using a tripartite model perspective. First, we contend that NMES does not actually bypass the central nervous system but results in a multitude of neurally mediated responses that contribute substantially to force generation and may engender neural adaptations. Second, we argue that too much emphasis is generally placed on externally controllable stimulation parameters while the major determinant of NMES effectiveness is the intrinsically determined muscle tension generated by the current (ie, evoked force). Third, we believe that a more systematic approach to NMES therapy is required in the clinic and this implies a better identification of the patient-specific impairment and of the potential "responders" to NMES therapy. On the basis of these considerations, we suggest that the crucial steps to ensure the clinical effectiveness of NMES treatment should consist of (1) identifying the neuromuscular impairment with clinical assessment and (2) implementing algorithm-based NMES therapy while (3) properly dosing the treatment with tension-controlled NMES and eventually amplifying its neural effects.

Muscle motor point identification is essential for optimizing neuromuscular electrical stimulation use.

Transcutaneous neuromuscular electrical stimulation applied in clinical settings is currently characterized by a wide heterogeneity of stimulation protocols and modalities. Practitioners usually refer to anatomic charts (often provided with the user manuals of commercially available stimulators) for electrode positioning, which may lead to inconsistent outcomes, poor tolerance by the patients, and adverse reactions. Recent evidence has highlighted the crucial importance of stimulating over the muscle motor points to improve the effectiveness of neuromuscular electrical stimulation. Nevertheless, the correct electrophysiological definition of muscle motor point and its practical significance are not always fully comprehended by therapists and researchers in the field. The commentary describes a straightforward and quick electrophysiological procedure for muscle motor point identification. It consists in muscle surface mapping by using a stimulation pen-electrode and it is aimed at identifying the skin area above the muscle where the motor threshold is the lowest for a given electrical input, that is the skin area most responsive to electrical stimulation. After the motor point mapping procedure, a proper placement of the stimulation electrode(s) allows neuromuscular electrical stimulation to maximize the evoked tension, while minimizing the dose of the injected current and the level of discomfort. If routinely applied, we expect this procedure to improve both stimulation effectiveness and patient adherence to the treatment.The aims of this clinical commentary are to present an optimized procedure for the application of neuromuscular electrical stimulation and to highlight the clinical implications related to its use.

Spinal involvement and muscle cramps in electrically elicited muscle contractions.

Electrical stimulation of innervated muscles has been investigated for many decades with alternations of high and low clinical interest in the fields of rehabilitation medicine and sports sciences. Early work demonstrated that afferent fibers have lower thresholds and are usually activated first (therefore eliciting an H-reflex). In the case of nerve trunk stimulation, the order of recruitment is mostly conditioned by the axonal dimension and excitability threshold. In the case of muscle motor point stimulation, the spatial distribution of nerve branches plays a predominant role. Sustained stimulation produces a progressive increase of force that is often maintained in subsequent voluntary activation by stroke patients. This observation suggested a facilitation mechanism at the spinal and/or supraspinal level. Such facilitation has been observed in healthy subjects as well, and may explain the generation of cramps elicited during stimulation and sustained for dozens of seconds after the stimulation has been interrupted. The most recent interpretations of facilitation resulting from peripheral stimulation focused on presynaptic (potentiation of neurotransmitter release from afferent fibers) or postsynaptic (generation of "persistent inward currents" in spinal motor neurons or interneurons) mechanisms. The renewed attention to these phenomena is once more increasing the interest toward electrical stimulation of the neuromuscular system. This is an opportunity for a structured investigation of the field aimed to resolving elements of confusion and controversy that still plague this area of electrophysiology.