
Martino V. FranchiUniversity of Padua | UNIPD · Department of Biomedical Sciences - DSB
Martino V. Franchi
MRes, PhD in Skeletal Muscle Physiology
Muscle plasticity in exercise, unloading & ageing
->eccentric actions; sarcomerogenesis; sports med; space physiology
About
149
Publications
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Introduction
Investigating, with an integrative physiology approach ("from the macro to the micro"), the architectural, functional, morphological and molecular mechanisms of skeletal muscle remodelling in response to loading, unloading and ageing.
Additional affiliations
May 2012 - May 2014
November 2013 - November 2014
November 2014 - May 2017
Publications
Publications (149)
Ultrasonography is widely used to assess skeletal muscle and tendon properties, such as architecture, cross-sectional area, and tissue stiffness. Despite its growing application in different scenarios, the lack of accessible and standardized public datasets limits large-scale studies and the development of image analysis algorithms. To address this...
Short‐term unloading experienced following injury or hospitalisation induces muscle atrophy and weakness. The effects of exercise following unloading have been scarcely investigated. We investigated the functional and molecular adaptations to a resistance training (RT) programme following short‐term unloading. Eleven males (22.09 ± 2.91 years) unde...
Competitive alpine skiing requires a high level of physical fitness to perform sport-specific manoeuvres and to minimise the risk of injury. The aim of this study was to establish reference values for the maximal anatomical cross-sectional area (ACSAmax) of the individual hamstrings (HAM) and quadriceps (QUAD) muscles as well as for the maximal vol...
Purpose: Adolescent soccer players experience distinct physiological changes due to chronological and biological maturation, impacting their soccer performance. Here, we explored age-related variations and associations between quadriceps geometry and strength in male national-level adolescent soccer players. Patients and Methods: We used ultrasonog...
Background Degeneration of the motoneuron and neuromuscular junction (NMJ) and loss of motor units (MUs) contribute to age-related muscle wasting and weakness associated with sarcopenia. However, these features have not been comprehensively investigated in humans. This study aimed to compare neuromuscular system integrity and function at different...
Objective
Existing literature indicates that females generally demonstrate higher fatigue resistance than males during isometric contractions. However, when it comes to single-limb dynamic exercises, the intricate interplay between performance fatigability (PF), cardiovascular responses, and muscle metabolism in relation to sex differences remains...
Background
Degeneration of the motoneuron and neuromuscular junction (NMJ) and loss of motor units (MUs) contribute to age‐related muscle wasting and weakness associated with sarcopenia. However, these features have not been comprehensively investigated in humans. This study aimed to compare neuromuscular system integrity and function at different...
PURPOSE: Resistance training (RT) prevents muscle atrophy and preserves muscle function in aging while eliciting sufficient metabolic demands to alter
mitochondrial homeostasis in old adults. Eccentric RT (ECC-RT) was suggested as a valid alternative to classic RT in the elderly, requiring less effort and energy
expenditure. However, it may exert p...
INTRODUCTION
Skeletal muscle aging is not only characterized by loss of muscle mass and power but also by mitochondrial impairments and reduced oxidative function (1). Resistance training (RT) is considered among the most effective strategies to preserve muscle atrophy and muscle function (2). Moderate intensity exercise based on eccentric (ECC) c...
Purpose
Prior evidence has shown that neural factors contribute to the loss of muscle force after skeletal-muscle disuse. However, little is known about the specific neural mechanisms altered by disuse. Persistent inward current (PIC) is an intrinsic property of motoneurons responsible for prolonging and amplifying the synaptic input, proportionall...
Background: Degeneration of motoneuron and neuromuscular junctions (NMJ) and loss of motor units (MUs) contribute to age-related muscle wasting and weakness, leading to sarcopenia. However, these features have not been adequately investigated in humans. This study aimed to compare neuromuscular system integrity and function across different stages...
Introduction: Short-term muscle unloading (~7-10 days) can be usually experienced following injury or hospitalisation, leading to muscle disuse atrophy, muscle weakness and changes in motor control. In such contexts, exercise countermeasures can be employed to overcome these neuromuscular impairments. Surprisingly, the effects of exercise counterme...
Background
Quantitative ultrasound (QUS) techniques are new diagnostic tools able to identify changes in structural and material properties of the investigated tissue. For the first time, we evaluated the capability of QUS techniques in determining the in vivo transient changes in knee joint cartilage after a stressful task.
Methods
An ultrasound...
Background
The Union of European Football Associations (UEFA) established a panel of experts to determine methodological recommendations for the conduct of studies which explore the acute effects of heading (defined as a single session of heading). This process was deemed necessary to improve the quality of studies which use heading trials to bette...
Aim: Force expression is characterized by an interplay of biological and molecu- lar determinants that are expected to differentiate males and females in terms of maximal performance. These include muscle characteristics (muscle size, fiber type, contractility), neuromuscular regulation (central and peripheral factors of force expression), and indi...
available online at https://doi.org/10.36950/2024.2ciss023
There is increasing concern regarding the effects of heading in football on brain health including cognitive, behavioural and neuromotor function, with research suggesting an association between repeated ball-head impacts and neurodegenerative disease. While longitudinal studies to determine the long-term consequences of heading are challenging, th...
Introduction: The mechanical properties of skeletal muscle are indicative of its capacity to perform physical work, state of disease, or risk of injury. Ultrasound shear wave elastography conducts a quantitative analysis of a tissue’s shear stiffness, but current implementations only provide two-dimensional measurements with limited spatial extent....
The aim of this study was to investigate the reliability of panoramic ultrasound (US) imaging and agreement with magnetic resonance imaging (MRI) for assessing the average lumbar multifidus anatomical cross-sectional area between the lumbar vertebral bodies L3–L5 (i.e., LMF ACSAL3–L5). US and MRI scans of 20 male youth competitive alpine skiers wer...
PURPOSE: High-density surface EMG (HDsEMG) provides valuable information about motor units (MUs) properties and their adaptability non-invasively. However, great intersubject variability in identification of MUs exists due to anatomical constraints of the muscle, individual volume conductor properties and the contraction intensity. A recent study s...
Objective:
B-mode ultrasound can be used to image musculoskeletal tissues, but one major bottleneck is analyses of muscle architectural parameters (i.e., muscle thickness, pennation angle and fascicle length), which are most often performed manually.
Methods:
In this study we trained two different neural networks (classic U-Net and U-Net with VG...
Ultrasound‐derived measurements of muscle fascicle length (FL) are often used to infer increases (chronic stretch or training) or decreases (muscle disuse or aging) in serial sarcomere number (SSN). Whether FL adaptations measured via ultrasound can truly approximate SSN adaptations has not been investigated. We casted the right hindlimb of 15 male...
As the detection and monitoring of skeletal mass are of primary importance in clinical settings and the ones more related to human performance, the need to assess changes in muscle size quickly and reliably is still fundamental. Muscle ultrasound represents a cheap and user-friendly, yet robust and reliable, method to monitor muscle mass in differe...
During natural aging, skeletal muscle experiences impairments in mechanical performance due, in part, to changes in muscle architecture and size, notably with a loss of muscle cross-sectional area. Another important factor that has received less attention is the shortening of fascicle length, potentially reflective of a decrease in serial sarcomere...
Ultrasound-derived measurements of muscle fascicle length (FL) are often used to infer increases (chronic stretch or training) or decreases (muscle disuse or aging) in serial sarcomere number (SSN). Whether FL adaptations measured via ultrasound can truly approximate SSN adaptations has not been investigated. We casted the right hindlimb of 15 male...
Background:
To non-invasively test the hypothesis that (a) short-term lower limb unloading would induce changes in the neural control of force production (based on motor units (MUs) properties) in the vastus lateralis muscle and (b) possible changes are reversed by active recovery.
Methods:
Ten young males underwent 10 days of unilateral lower l...
This study aimed (i) to investigate the role of regional characteristics of the knee extensors muscles (vastus lateralis: VL, vastus intermedius: VI and rectus femoris: RF) in determining maximum-voluntary force (MVF); and (ii) to understand which regional parameter of muscle structure would best predict MVF. Muscle architecture (e.g., pennation an...
The purpose of this study was to compare the effects of electromagnetic resistance alone, as well as in combination with variable resistance or accentuated eccentric methods, with traditional dynamic constant external resistance exercise on myoelectric activity during elbow flexion. The study employed a within-participant randomized, cross-over des...
Ultrasound-derived measurements of fascicle length (FL) are often used to infer increases (e.g., with chronic stretch or training) or decreases (e.g., with aging) in the number of serially aligned sarcomeres (serial sarcomere number; SSN). Despite the widespread use of ultrasound imaging to assess FL adaptations, whether ultrasound can truly approx...
Physical inactivity represents a heavy burden for modern societies and is spreading worldwide, it is a recognised pandemic and is the fourth cause of global mortality. Not surprisingly, there is an increasing interest in longitudinal studies on the impact of reduced physical activity on different physiological systems. This narrative review focuses...
Introduction: Physical inactivity is a main curse of modern society, characterized by neuromuscular decline with progressive loss of muscle mass, strength, and power and by an increased risk of major chronic diseases. Exercise countermeasures seem to be highly beneficial for contrasting neuromuscular impairments; however, there is a paucity of data...
Introduction: Mounting evidence suggests that motoneuron and neuromuscular junction (NMJ) degeneration, muscle fiber denervation and loss of motor units contribute to muscle wasting and weakness in old age. However, these aspects are still poorly investigated in humans. This study aimed at comparing the neuromuscular system integrity and function o...
Human skeletal muscle atrophy and a disproportionate force loss occur within a few days of unloading in space and on Earth, but the underlying mechanisms are not fully understood. Disruption of neuromuscular junction homeostasis has been proposed as one of the possible causes. Here, we investigated the potential mechanisms involved in this neuromus...
From a preventative perspective, leg axis and core stabilization capacities are important for soccer players and alpine skiers; however, due to different sport-specific demands, the role of laterality clearly differs and may result in functional long-term adaptations. The aims of this study are 1) to determine whether there are differences in leg a...
Although ultrasonography is commonly used to assess muscle architecture, high-end ultrasonography devices lack in portability and are expensive. Recently, ultrasonography devices consisting solely of a probe, an app, and/or a mobile display were introduced. These devices have lower acquisition costs than high-end devices and demonstrate higher port...
B-mode ultrasound is commonly used to image musculoskeletal tissues, but one major bottleneck is data analysis. Manual analysis is commonly deployed for assessment of muscle thickness, pennation angle and fascicle length in muscle ultrasonography images. However, manual analysis is somewhat subjective, laborious and requires thorough experience. We...
Background
Ageing is accompanied by a progressive loss of skeletal muscle mass and strength, potentially determining the insurgence of sarcopenia. Evidence suggests that motoneuron and neuromuscular junction (NMJ) degeneration contribute to sarcopenia pathogenesis. Seeking for strategies able to slow down sarcopenia insurgence and progression, we i...
Background
The lumbar multifidus (LMF), as a dynamic stabilizer of the lumbar spine, may play an important role in the prevention of overuse-related back complaints.
Hypothesis
LMF morphology is associated with trunk stability and differs between symptomatic and asymptomatic skiers.
Study Design
Cohort study.
Level of Evidence
Level 3.
Methods...
Background
Inactivity and unloading induce skeletal muscle atrophy, loss of strength and detrimental metabolic effects. Bed rest is a model to study the impact of inactivity on the musculoskeletal system. It not only provides information for bedridden patients care, but it is also a ground-based spaceflight analogue used to mimic the challenges of...
Physical inactivity (PI) is a major risk factor of chronic diseases. A major aspect of PI is loss of muscle mass and strength. The latter phenomenon significantly impacts daily life and represent a major issue for global health. Understandably, skeletal muscle itself has been the major focus of studies aimed at understanding the mechanisms underlyi...
Electrophysiological alterations of the neuromuscular junction (NMJ) and motor unit potential (MUP) with unloading are poorly studied. We aimed to investigate these aspects and the underlying molecular mechanisms with short‐term unloading and active recovery (AR). Eleven healthy males underwent a 10‐day unilateral lower limb suspension (ULLS) perio...
Lower extremity injuries are common in competitive alpine skiers, and the knee and lower leg are often affected. The hamstring muscles, especially the biceps femoris long head (BFlh), can stabilize the knee and the hip and may counteract various adverse loading patterns during typical mechanisms leading to severe lower extremity injuries. The aim o...
High end ultrasonography devices lack in portability and are expensive. We investigated the agreement and reliability of a handheld and portable ultrasound system for human lower limb muscle architecture measurements. We captured ultrasound images of the rectus femoris (RF), vastus lateralis (VL) and gastrocnemius medialis (GM) in 36 active healthy...
Although regular physical activity exposure leads to positive postural balance control (PBC) adaptations, few studies investigated its effects, or the one of inactivity, on PBC in populations of different age groups. Thus, this study investigated the impact of a physically active lifestyle on static and dynamic PBC in young and older adults. Thirty...
Exercise training can induce adaptive changes to tendon tissue both structurally and mechanically; however, the underlying compositional changes that contribute to these alterations remain uncertain in humans, particularly in the context of the ageing tendon. The aims of the present study were to determine the molecular changes with ageing in patel...
Purpose:
Muscle anatomical cross-sectional area (ACSA) can be assessed using ultrasound and images are usually evaluated manually. Here, we present DeepACSA, a deep learning approach to automatically segment ACSA in panoramic ultrasound images of the human rectus femoris (RF), vastus lateralis (VL), gastrocnemius medialis (GM) and lateralis (GL) m...
Purpose:
The hamstrings (HS) muscle group plays a fundamental role in maintaining knee stability, thus contributing to the prevention and rehabilitation of lower limb musculoskeletal injuries. However, little is known about HS structural and functional adaptations after periods of prolonged inactivity. Our purpose was to investigate the HS morphol...
Increased serial sarcomere number (SSN) has been observed in rats following downhill running training due to the emphasis on active lengthening contractions; however, little is known about the influence on dynamic contractile function. Therefore, we employed 4 weeks of weighted downhill running training in rats, then assessed soleus SSN and work lo...
Astronauts experience dramatic loss of muscle mass, decreased strength and insulin resistance, despite performing daily intense physical exercise that would lead to muscle growth on Earth. Partially mimicking spaceflight, prolonged bed rest causes muscle atrophy, loss of force and glucose intolerance. To unravel the underlying mechanisms, we employ...
Patellar tendon (PT) complaints are frequent throughout the population, with increased occurrence in athletes and, particularly, in youth competitive alpine skiers. Timely detection and treatment might improve prospects of recovery. Diagnostic modalities in clinical use to date rely on pain symptoms, manual palpation, and potentially, magnetic reso...
Skeletal muscle has the remarkable ability to remodel and adapt, such as the increase in serial sarcomere number (SSN) or fascicle length (FL) observed after overstretching a muscle. This type of remodelling is termed longitudinal muscle fascicle growth, and its impact on biomechanical function has been of interest since the 1960s due to its clinic...
Aim:
We planned a cross-sectional investigation (study 1) and a longitudinal training intervention (study 2) to investigate whether recreational dancing affords greater neuroprotective effects against age-related neuromuscular junction (NMJ) degeneration compared to general fitness exercise training.
Methods:
In study 1, we recruited 19 older vo...
Various tests are available to assess athletes for factors associated with their susceptibility
and risk of anterior cruciate ligament (ACL) injury or reinjury; however, it is unclear which tests are clinically meaningful and what should be considered when using them. Therefore, the aim of this scoping review was to screen and summarize testing and...
Introduction
The insertion/deletion (I/D) polymorphism in the gene for the major regulator of vascular tone, angiotensin-converting enzyme-insertion/deletion (ACE-I/D) affects muscle capillarization and mitochondrial biogenesis with endurance training. We tested whether changes of leg muscle oxygen saturation (SmO 2 ) during exhaustive exercise and...
Increased serial sarcomere number (SSN) has been observed in rats via downhill running training due to the emphasis on active lengthening contractions; however, little is known about the influence on dynamic contractile function. Therefore, we employed 4 weeks of weighted downhill running training in rats, then assessed soleus SSN and work loop per...
Background: Muscle anatomical cross-sectional area (ACSA) is an important parameter that characterizes muscle function and helps to classify the severity of several muscular disorders. Ultrasound is a patient friendly, fast and cheap method of assessing muscle ACSA, but manual analysis of the images is laborious, subjective and requires thorough ex...
Background: Eccentric exercise is widely used to increase muscle fascicle lengths and thus decrease the risk of muscle strain injuries. It is commonly assumed that increased sarcomere number drives this training adaptation and reduces risk of muscle strain, however this has yet to be experimentally tested. This study used a new microendoscopy techn...
The aim was to investigate the potential differences in muscle (vastus lateralis) and cerebral (prefrontal cortex) oxygenation levels as well as in the number of repetitions and total work output between isokinetic eccentric and concentric exercise at a moderate relative intensity until exhaustion. Ten recreationally active young men underwent two...
Background
Eccentric exercise increases muscle fascicle lengths; however, the mechanisms behind this adaptation are still unknown. This study aimed to determine whether biceps femoris long head (BFlh)¹ fascicle length increases in response to 3 weeks of eccentric exercise training are the result of an in-series addition of sarcomeres within the mus...
Background & aims
The skeletal muscle anabolic effects of n-3 polyunsaturated fatty acids (n-3 PUFA) appear favoured towards women; a property that could be exploited in older women who typically exhibit poor muscle growth responses to resistance exercise training (RET). Here we sought to generate novel insights into the efficacy and mechanisms of...
As the excitation–contraction coupling is inseparable during voluntary exercise, the relative contribution of the mechanical and neural input on hypertrophy-related molecular signalling is still poorly understood. Herein, we use a rat in-vivo strength exercise model with an electrically-induced standardized excitation pattern, previously shown to i...