Caratteristiche delle sinergie muscolari dell'arto superiore, in soggetti sani e con diagnosi di ictus: revisione della letteratura

Background e obiettivi: L'impairment dell’arto superiore rappresenta, per l’incompletezza del recupero e l’impatto sulla qualità di vita che ne deriva, un aspetto di rilievo nei soggetti con diagnosi di ictus. Tuttavia, l’eterogeneità dei quadri motori ha da sempre rappresentato una difficoltà per lo sviluppo di evidenze della validità ed efficacia delle strategie fisioterapiche, probabilmente per un maggior focus della ricerca sugli effetti della riabilitazione a livello periferico, piuttosto che cercare di comprendere i meccanismi neurofisiologici centrali alla base del controllo motorio. In questo contesto si inserisce quindi il presente disegno di studio che, sostenendo l’ipotesi delle sinergie muscolari quale strategia del Sistema Nervoso Centrale per organizzare il movimento, ha come obiettivo di individuare le caratteristiche dei moduli motori nelle popolazioni con ictus e confrontarli con quelli registrati nei soggetti sani, al fine di individuare le eventuali alterazioni neurofisiologiche che un evento cerebrovascolare determina nell’organizzazione motoria dei movimenti volontari dell’arto superiore. Materiali e metodi: La presente tesi, redatta seguendo le linee guida PRISMA, fa riferimento al protocollo di revisione registrato su PROSPERO il 1 ottobre 2021 (ID: CRD42021275657). In particolare sono state consultate le seguenti banche dati: PubMed, CINAHL, Scopus, Web of Science, Cochrane ed Embase, dalle quali sono stati raccolti da due revisori indipendenti gli articoli che rispettassero i criteri di inclusione definiti a priori. In caso di disaccordo, un terzo revisore è intervenuto per prendere le decisioni finali. Una volta valutata l'inclusione degli studi, sono stati estratti e raccolti i dati in tabelle sinottiche. Risultati: Quarantotto studi sono stati analizzati per l'estrazione dei dati. Per ognuno di questi sono state raccolte le informazioni relative a campione, disegno di studio, definizione di sinergia muscolare, algoritmo di estrazione, numero e composizione dei moduli motori. Discussione e conclusioni: La mancanza di omogeneità rispetto alla definizione dei protocolli sperimentali ha reso i dati raccolti solo parzialmente confrontabili. Studi con caratteristiche affini hanno evidenziato sinergie quantitativamente simili in popolazioni con impairment motorio da lieve a moderato rispetto al gruppo di controllo sano. Risultati contrastanti sono invece emersi nei soggetti con disabilità di grado severo. Composizioni diverse sono state individuate nella maggior parte degli studi, per cui in termini di attivazioni muscolari non è stato possibile descrivere una valida panoramica dei moduli motori nei soggetti sani e con diagnosi di ictus.Background and objectives: Due to difficult in recovery and impact on quality of life, impairment of the upper limb represents the major issue in individuals diagnosed with stroke. However, heterogeneity of motor prognosis has always represented a difficulty for the development of valid and efficient physiotherapy strategies, probably due to a greater focus of research on the effects of rehabilitation at the peripheral level, rather than trying to understand the central neurophysiological mechanisms underlying motor control. This is the context for the present study design which, supporting the hypothesis of muscle synergies as a Central Nervous System strategy to organise movements, aims to identify the characteristics of motor modules in stroke populations and to compare them with those recorded in healthy subjects, in order to identify any neurophysiological alterations that a cerebrovascular event determines in motor control of voluntary movements of the upper limb. Materials and methods: This thesis followed the PRISMA guidelines and refers to the review protocol registered on PROSPERO on 1st October 2021 (ID: CRD42021275657). The following databases were consulted: PubMed, CINAHL, Scopus, Web of Science, Cochrane and Embase. Articles accomplishing defined inclusion criteria were screened by two independent reviewers. A third reviewer solved eventual disagreement. Data from included studies were extracted and collated in synoptic tables. Results: Forty-eight studies were analysed for data extraction. For each of these, information on sample, study design, definition of muscle synergy, extraction algorithm, number and composition of motor modules was extracted. Discussion and conclusions: The lack of homogeneity with respect to the definition of the experimental protocols made the collected data only partially comparable. Studies with similar characteristics showed quantitatively similar synergies in populations with mild to moderate motor impairment, compared with healthy control subjects. Conversely, contrasting results emerged in subjects with severe impairment. Different compositions were found in most of the studies, thus was not possible to describe a valid overview of the motor modules in healthy and stroke-diagnosed subjects at the level of muscle activations

THE EFFECTS OF CONSECUTIVE SOFTBALL WINDMILL PITCHES ON COORDINATION PATTERNS AND VARIABILITY, MUSCULAR STRENGTH, AND PITCHING PERFORMANCE

Upper and lower extremity musculoskeletal injuries occur at a similar rate in softball pitchers. Most of these injuries can be considered chronic in nature, which may result in symptoms being treated instead of considering the underlying mechanism for injury. Previous literature has primarily focused on discrete values such as joint ranges and kinematic peaks. The primary purpose was to examine inter-segmental and intra-limb coordination of the softball windmill pitch throughout a simulated game of softball and to determine if variability of these patterns change throughout multiple pitch counts. The secondary purpose is to identify if a difference between pre-pitching and post-pitching strength can be detected to determine if muscular fatigue, as defined by the inability to sustain the expected power output around a joint, has occurred. Pitching performance, defined as pitch velocity and accuracy, were also assessed. A total of 14 softball pitchers (17.9±2.3 years, 166.4±8.67 cm, 72.3±12.6 kg) successfully completed all strength assessments and pitching sequence. Pitchers completed strength assessments of the at baseline and immediately after a pitching sequence consisting of 105 fastballs. Vector coding was used to measure coordination and variability of Drive Leg Thigh v Pelvis, Pelvis v Torso, Pelvis v Humerus and Humerus v Forearm. Paired t-test or Wilcoxon Signed Ranks test was used to determine change in muscular strength. One-way repeated measures analysis of variance was performed to establish if differences in pitch velocity or accuracy varied between innings. Appropriate order parameter to encapsulate the behavior of the windmill pitch could not be established due to lack of fatigue or incorrect coordinative structures measured. Results demonstrated a significant increase in stride leg knee extension and trunk flexion peak torque, as percent body weight, after consecutive pitches. Differences were seen in pitch velocity but not accuracy across innings. While this study did not demonstrate the negative effects of consecutive pitching that were expected, results can provide a foundation for future research into windmill pitch mechanics to assist with injury prevention and performance optimization