This systematic review was developed based on the favored reporting items for systematic reviews and meta-analyses (PRISMA) guidelines (26). The studies were selected through a database screening, such as PubMed (NLM) Web of Science (TS), and Scopus. The following keywords have been included to identify the articles: exercise, physical activity, telecoaching, tele-coaching, Charcot–Marie-Tooth, aerobic training, resistance training, and training. Terms were included in three different groups. In Group A the terms “telecoaching” and “tele-coaching” were inserted, in Group B the terms “exercise,” “physical activity,” “aerobic training,” “resistance training” and “training” were inserted. Finally, in Group C has been inserted the “Charcot–Marie-Tooth” term. To analyze the groups, Boolean operators “AND” and “OR” were used. Examples of matching included: Charcot–Marie-Tooth AND aerobic training OR telecoaching; resistance training AND Charcot–Marie-Tooth. All the founded articles were transferred into the Endnote software (Vers. X20 for Windows 11, © Thomson Reuters).

All studies that have the following criteria were included in this systematic review: (1) original research with full text written in the English language; (2) all study designs different than reviews, meta-analyses, letters to editors, and theses; (3) studies with training protocol in TC for patients with CMT. No gender differences between males and females were used for exclusion criteria. Articles from gray literature have not been investigated. The PICOS approach (Population, Intervention, Comparator, Outcomes, Study design) is explained in Table 1.

The identification and elimination of duplicate studies were carried out by a single researcher. Subsequently, two authors analyzed independently the articles. Initially, the authors analyzed the title and abstracts of each study. Secondly the authors analyzed the full text to assess whether the selected studies agreed with the criteria of inclusion and exclusion.

The two authors discussed any dispute regarding their decisions; if the two authors did not agree on the inclusion or exclusion of a study, a third auditor was consulted. A Microsoft Excel spreadsheet (Microsoft Corp, Redmond, Washington) was used to report the following information related to the included studies: year of publication, sample age, gender, the aim of the study, and the TC protocol.

Two authors evaluated the quality and bias of all the studies included in this review, using a modified version of the checklist to measure the quality of RCTs and not RCTs written by Downs and Black (27). In the modified version of the checklist, item 27 (power) was changed from 0 to 5 to a score of 0–1, so that a study would receive a score of 0 in case the statistical power was below 80%, a score of 1 if the statistical power was above 80% (28). As a result, the final checklist score changed from 32 to 28. The quality of the studies was divided into four levels: excellent (26–28), good (20–25), fair (15–19), and poor (<14) (29, 30). The authors’ results were compared by an external researcher and discrepancies were resolved in a consensus meeting.

A total of 382 studies were identified through electronic databases. The titles and abstracts of 199 studies were analyzed after removing 183 duplicates. The full text of 17 studies has been examined of which only 7 articles agree with the inclusion and exclusion criteria. The PRISMA flowchart shows the entire selection process (Figure 1).

In detail, of the 7 included studies, 5 analyzed the effectiveness of a resistance training protocol in patients with CMT (31–35), while 2 studies analyzed the effectiveness of an interval training protocol on this target population (36, 37).

A total of 170 patients with CMT were included in this review with an age between 11 and 45 years. Of the 7 studies, it is possible to identify two studies of El Mhandi et al. (36, 37) that included only male participants. The other five studies included both male and female participants. More detailed information on each study can be found in Table 2.

The methodological quality of the included studies was analyzed using the modified version of the Downs and Black checklist. Out of 7 studies, 1 study was evaluated as “good quality” (34), 3 studies as “fair quality” (31, 33, 35), and 3 studies were evaluated as “poor quality” studies (32, 36, 37). Some items of Downs and Black are difficult to use in studies with physical activity protocol, such as the use of a study design in double-blind.

Of the extrapolated studies, five used a TC resistance training protocol in patients with CMT (31–34). Among these, there is the study of Burns and colleagues (31); a randomized, double-blind, sham-controlled trial, in which the experimental group performed a TC training resistance exercise, while the control group performed a fictitious workout. The treatment team was the only one who knew about group assignment; participants, parents, caregivers, clinical evaluators, and other investigators were not informed of the group allocation. The experimental group, consisting of children, had performed a TC training program that aimed to improve the weakness in the dorsiflexion of the foot. Participants were trained using an adjustable ankle bracelet, designed to prevent slipping, three times a week or non-consecutive days, for 6 months with a protocol that provided an initial intensity of 50% and a progressive increase of up to 70% of one repetition maximum (1RM). The control group trained with the same procedure, including the same equipment, the same duration, the same frequency, the same series, and repetitions. However, the participants trained with a very low intensity, never exceeding 10% 1RM. Each parent was asked to help the child with the application of the bracelet and to supervise the training performed in TC. TC included the compilation of an exercise diary, the delivery of a video to be used as a familiarization, and the active participation of parents as a guide, as well as the execution of some supervised training sessions. The results indicated that after a 24-week intervention period, the experimental group had reduced the long-term progression of dorsiflexion weakness without side effects on muscle morphology; there were no signs of overwork fatigue. It has been shown that a TC training program is safe, valid, and effective in a pediatric population affected by CMT disease. A drop-out of 5 patients was detected, demonstrating high adherence to the training mode. Also Chetlin’s study (34) used a home-based resistance training program, for 12 weeks. This study aimed to evaluate the efficacy of resistance training with and without creatine supplementation on muscle strength and activities of daily living (ADL) in patients with CMT disease. ADL included getting up from the chair without using your arms, getting up from a supine position, and going up and down the stairs. The subjects were also timed while performing a lifting and moving test. Each test was performed from 3 to 6 times. In detail, 20 patients with CMT consumed 5 g/day creatine or placebo, while participating in a resistance training program. Resistance training consisted of 12 weeks of exercise performed in TC, divided into three phases (each phase of 4 weeks) with the amount of work increased systematically by adjusting the resistance or repetitions for each of the phases. For example, hand-grip exercises consisted of 3 sets of 4 repetitions, three times per week, with a 1-min rest period between each set. If the subjects failed to perform the number of repetitions, they used a lower resistance to complete the required program. More details can be found in Table 3. TC included the delivery of videos describing in detail the training techniques as well as supervised training sessions in which subjects knew the exercises to be performed.

The results indicated that for both groups, the type I muscle fiber diameter, and strength, were improved as well as the ADL. Overall, patients with CMT respond to resistance training performed in TC with muscle fiber adaptations, and with improvements in strength, and in the ADL. However, the use of Creatine was not beneficial. No drop-out has been detected.

The same research design has been applied by Chetlin and colleagues (32) to determine the effectiveness of a TC resistance training program on body composition, strength, and function of daily activities in men and women with CMT. The women’s group consisted of 11 participants while the men’s group of 9. At baseline, women had a normal percentage of strength (80%) in 4 out of 10 measurements, while men did not reach 80% of normal force in any measure. After resistance training, women reached 80% of normal strength in 8 out of 10 measurements, while men in 1 measurement. The functions of daily activities were improved after training without gender differences; moreover, men had significantly more fat-free mass (p < 0.05) before and after training compared to women.

Ramdharry and colleagues (33) used a randomized single-blind crossover design to assess the effectiveness of a physical exercise in TC on hip flexor muscle strength. Randomization was used to assign the subjects to one of two groups: group A with initial training, and group B with initial control period. The training protocol conformed with the guidelines of the American College of Sports Medicine (ACSM) and provided 16 weeks of training with 4 weekly training (38). Weights were used, positioned in the ankle, with periodic increments of 0.5 kg and oscillation from 40 to 60% of the maximum voluntary isometric contraction (MVC). Participants performed 2 sets of 8–12 repetitions, 4 days a week for 16 weeks. The exercise was performed in the supine position with load displacement from 10° in hip extension to 45° in hip flexion. After a period of familiarization, patients were monitored through an exercise diary, weekly phone calls, and monthly visits to improve protocol adherence. The results showed a significant increase in the strength of the hip flexor muscles to the left but not to the right, demonstrating that the resistance training was well-tolerated without evidence of weakness from overload. In addition, no drop-out was recorded, indicating high compliance with this training mode.

Finally, Dudziec and colleagues (35) used TC training protocol to assess the effectiveness of resistance training and multisensory balance training, delivered at home, on the ability to balance in patients with CMT. 14 patients were randomized into two groups: the TC group performed 12 weeks of strength training and multisensory balance; the control group performed the daily activities. The results showed high adherence to this training modality with 93% of patients completing the study. Posturography tests showed improvement in postural stability in favor of the intervention group, and the ability to balance and gait showed an improved elevated in the TC group. In the same group, partial improvements have been shown in the strength of the lower limbs.

Only two of the studies analyzed have used a TC protocol of interval training. El Mhandi and colleagues (37) have used this training program to assess if 24 weeks of interval training cycles could significantly improve physiological, neuromuscular, and functional abilities, as well as alleviate the perception of fatigue in patients with CMT. The training program included 24 weeks of training of which 12 were supervised and 12 telecoaching-independently at home. The single training session was 45 min and included 5 min of warm-up, 30 min of the middle phase, and 10 min of cool-down. No stretching activity was foreseen. The central phase consisted of 6 exercises of 5 min, of which 4 min at 40% of the maximum aerobic power (Pmax) and 1 min at 80% of Pmax. The exercise was made on stationary cycloergometers. TC period was performed with the same protocol, although several personal cycloergometers were used by subjects in their homes. Subjects were motivated and checked by weekly phone calls. The training period was well tolerated; no subjects reported adverse events or complications during the protocol. The results showed significant improvements in cardiorespiratory abilities, functional ability, and isokinetic strength, as well as in the scale of pain and fatigue during training. Also, benefits obtained at the end of the supervised period were maintained after the home period. However, the results also revealed that there was no effect on the production of isometric strength and indices of fatigue resistance after training.

The same training protocol was applied by El Mhandi and colleagues (36) to assess the effectiveness of interval training on heart rate variability (HRV) in patients with CMT. An experimental group and a healthy control group were included in this study. The HRV assessment was conducted at the baseline (T0) and the end of the 24-week study period (T1); in both evaluations, subjects were monitored through 24-h Holter electrocardiographic (ECG). The results showed that at the baseline all HRV indices of the experimental group were lower than the control group with a statistically significant difference for the pNN50 parameter. After the training program, the researchers found improvement in some time and frequency parameters in the experimental group; in some cases, the values of the experimental group at T1 exceeded the values of the control group at baseline (+8% mean R–R interval, +95% pNN50, 52% reduction in low/high-frequency ratio). These results suggest that interval training might improve dysautonomia in CMT, improving the activity of the parasympathetic nervous system.

A training program performed in TC has already been used in many other target populations, resulting in effective and risk-free (61, 62). From the analysis of these studies, it is possible to observe the main strengths and limitations of this new training approach. Indeed, the execution of physical exercise in TC has several advantages, among these we can identify the reduction of economic resources, the reduction of geographical limits, the freedom to train when you want as well as the possibility of training in a family environment and safe. In addition, this mode increases the autonomy and independence of the patient. However, TC has also negative factors, including social isolation, loss of contact between coach and patient, the high risk of abandonment, and the difficulty for the patient to understand the right execution technique of the exercises.

For these aspects, physical exercise in TC requires telecoaches flexible and available to every need of the patient, constant weekly calls in order to supervise and control the progress of the exercise as well as an initial familiarization in order to learn and improve the execution of the exercises. Moreover, to optimize the effectiveness of this training modality, could be useful to provide each patient a clear and concise digital material that explains in detail the exercises to be performed, such as demo videos. Another important tool could be an exercise diary, in which to record when the training is carried out and any personal considerations in order to optimize PA.