*3.1.1.2 Electromyography*

In **Table 2**, an interesting new technology capable of evaluating variations in muscle activity is shown: the EMG.

It was demonstrated [17] that some electrophysiological sarcopenic variables were associated with the frailty phenotype [8, 17], but frailty in older men was associated with lower CMAP and MUP, which however were not related to age and BMI.

On the basis of the data obtained by Habenicht et al. [26] in their study on back extension, a diagnostic algorithm for assessing the first signs of muscle weakness


*CSS, cross-sectional studies; CS, cohort studies; RCT, randomized control trials; OA, older adult; C-D, community-dwelling; JM, jumping mechanography; BIA, biological impedance analysis; DXA, dual-energy X-ray absorptiometry; BMI, body mass index; EFI, Esslinger fitness index; HF, history falls; MF, muscle function; 2LJPrel, maximum 2 leg jump power per kg body mass; CRTPrel, maximum chair rise test power per kg body mass; CRTV, the max velocity of the CRT; HGS, hand-grip strength; GS, gait speed; SPPB, short physical performance battery; JRP, jumping relative power; APT, acceptability; W or WALK, walking; EX, exercises; F&C, feasibility & compliance; DI&EH, dietary intakes & eating habits; MD, muscle density; M-CSA, muscle cross-sectional area; IMAT, intramuscular adipose tissue; MM, mobility measures; MATH, masters athletes; ATH, athletes; 23RD-WMAC, 23rd-World Masters Athletics Championships.*

#### **Table 3.**

*General overview of papers based on jumping mechanography.*

#### *Sarcopenia: Technological Advances in Measurement and Rehabilitation DOI: http://dx.doi.org/10.5772/intechopen.101278*

related to back extension may be developed [26]. Subsequently, Gennaro et al. [28], in their ES, defined "*corticomuscular coherence*" (CMC), obtained during locomotion by simultaneously measuring EEG and EMG, and suggested it as a new feature for the diagnosis of sarcopenia [28], reporting that it has a high sensitivity and specificity.

Marshall et al. [27] compared BW-RET with MN-RET and EB-RET in a group of healthy younger adults and a group of older adults: BW-RET proved less effective than MN-RET and EB-RET. The EMG parameters were defined by studying a population composed of young adults, healthy and at-risk older adults [29] (as shown in **Table 2**). In the article, they concluded that it was not clear if EMG difference correlates with MS loss or mere loss of muscle mass [29].

#### *3.1.1.3 Jumping mechanography*

The association between the jumping mechanography (JM) and sarcopenia starts with Buehring et al. [30, 31], who gave "operational definitions of the variables available through muscle mechanography" with the aim to propose muscle mechanography as a tool for what we defined as MQ parameter [31], supporting the reproducibility of JM in older people [30, 32].

To assess muscle function and, at the same time, the MQ and PP parameters, JM can be considered an interesting new tool. It was first described by Dietzel et al., Siglinsky et al., Hannam et al., and Gangnon et al. [30, 32–34]; in all of these studies, JM was performed by Leonardo Mechanograph® (**Table 3**). JM measures the peak of muscle power by a vertical jump, as this practice is considered safe and useful to assess not only MQ and PP parameters but also different geriatric outcomes clearly important in primary prevention.

In all previous studies, participants were tested in accordance with the first EWGSOP guidelines [32, 33] and showed a better correlation between ADL and JM performance. Such correlation gives useful indications for the prevention of falls and fractures. In another work [34], the feasibility and acceptability of JM were evaluated: JM was considered comfortable and the comfort was related to one's own JM performance.

Also, in the work by Alvero-Cruz et al. [36], sarcopenia was diagnosed according to the first EWGSOP guidelines. They did not use JM but studied highly trained track and field athletes to explain the age-related decline in vertical jumping performance, obtaining data from the Redcap, Leonardo, and BIA data merging [36].

Of interest, in 2020 a complete and well-designed RCT was carried out [35]. It consisted of an intervention program based on physical exercises to evaluate outcomes in anthropometrics, body composition, muscle function, mobility measures, JM, and dietary habits. It showed that the program could be feasible in a population of older adults and that JM detected differences in MS and MQ using the chair-rise test rather than the TUG test [35].

All the above-mentioned studies were carried out on the basis of the first EWGSOP guidelines. However, it is now necessary to perform studies comparing results with the second EWGSOP guidelines. Wiegmann et al. defined a diagnostic algorithm on the basis of the 2nd EWGSOP guidelines [37].

#### *3.1.1.4 Sarcopenia and BIA's phase angle*

The BIA's phase angle (PhA) was mentioned, not for the first time, in a work by Heymsfield et al. [7]. Biological impedance analysis (BIA) was considered a useful tool for sarcopenic patients who were unable to perform a handgrip test or to walk [4, 38, 39]. Nowadays, BIA is used to confirm the diagnosis of sarcopenia (**Table 4**).


*CSS, cross-sectional studies; CS, cohort studies; BIVA, bioelectrical impedance vector analysis; BIA, biological impedance analysis; DXA, dual-energy X-ray absorptiometry; 4-mWST, 4-m walking speed test; HGS, hand-grip strength; CES, center for epidemiologic studies, DS, depression scale (Mexican version); MMSE, mini-mental state examination; MNA-SF, mini nutritional assessment-short form; PhA, phase angle; NRS-2002, Nutritional Risk Screening 2002; DT, drawing test.*

#### **Table 4.**

*General overview of the relationship between the assessment of sarcopenia and BIA's phase angle.*


*CSS, cross-sectional study; RCT, random controlled trial; SC-D, sarcopenic community-dueling; C-D, communitydueling; DVS, design and validation study; HP, healthy participants; SP, sarcopenic participants; BIA, biological impedance analysis; MRI, magnetic resonance imaging; 6 MW, six minutes walking; QMVC, maximum voluntary quadriceps contraction; TwQ, maximum quadriceps twitch tension.*

#### **Table 5.**

*General overview of the paper focused on the assessment of sarcopenia: New tools and software.*

According to a study carried out in Mexico [40] on active older women, there seems to be no correlation between PhA and sarcopenia parameters, but PhA seems to be associated, with a doubtful biological meaning, with speed walking [40] (or PP). In a recent paper [41], they analyzed sarcopenia on the basis of the parameters defined by the second EWGSOP guidelines, and physical frailty, according to the parameters defined by Fried et al. [8], both adjusted to the Mexican population.

Studies on more homogeneous populations may clarify the usefulness of BIA's PhA.

## *3.1.1.5 New technologies tested*

Magstim 200 system: Magnetic nerve stimulation was tested on older sarcopenic people [42]. The study reports several limitations in the execution and screening of sarcopenic patients whose functions were not highly compromised. Despite this and the fact that it is an expensive technique, this methodology is still considered acceptable and feasible. More tests on sarcopenic patients with highly impaired functionality would be needed (**Table 5**).

Software HTSMavor: In South America, accessibility to DXA is very difficult. With the purpose to facilitate the assessment of sarcopenia, a screening algorithm for the diagnosis of sarcopenia, following the second EWGSOP guidelines, was developed. The results are very promising, but software accuracy for different populations should be implemented [43].

Bioelectrical impedance analysis to estimate the lean muscle volume: Serial bioelectrical impedance analysis (SBIA) was compared with magnetic resonance imaging (MRI) [44]. As a strong agreement between IVBIA and IVMRI was found, a specific conductivity constant () was computed in order to assess the reliability of SBIA as a possible alternative to MRI. Despite the study limitations, the technique appears to be very promising.

#### *3.1.2 Rehabilitation in sarcopenia*

Sarcopenic patients are not usually followed in the daily routine, therefore it would be advisable to develop rehabilitation programs to keep the progression of the disease under control. Rehabilitation programs usually contain enhanced physical exercises and dietary increased amounts of protein intake [45]. In the absence of these rehabilitation programs, physicians give advice on physical exercises and dietary habits to patients. However, these recommendations are rarely observed by the patients [46].

In the following part of this manuscript, we talk about new proposals on rehabilitation. Such proposals include new or old technologies that could be used in planned therapies for pre-sarcopenic and sarcopenic patients.

### *3.1.2.1 Virtual reality and laser therapy*

Thousands of articles on rehabilitation protocols that use virtual reality in different research fields have been produced [47, 48], but there are still few studies applying virtual reality to sarcopenia. The patients on whom the usability was tested were older patients with varied pathologies. The results were promising; therefore, it is hoped that it will be applicable to sarcopenic patients (**Table 6**).

In the work by Chen et al. [50], the virtual reality-based progressive resistance training was tested on patients residing in a nursing home, over a period of 12 weeks. The outcomes were different, but the training determined an improvement especially of the upper limb strength, in other words, MS and MQ but not PP. An increase of ASMM was present but was not statistically significant [50]. Further studies are required.


*RTC-DB, randomized control trial-double blinded; Q-ES, quasi-experimental study; SR, systematic review; VR-RHE, virtual reality-based progressive resistance training; ORH, oculus rift headset; LMS, leap motion sensor; VR, virtual reality; CG, control group; LLLT, low-level laser therapy; TG, strength training associated with placebo LLLT; TLG, strength training associated with active LLLT; BS, blood sample; HGS, hand grip strength; GS, gait speed; BIA, biological impedance analysis; OA, older adult; YA, young adult; SUS, system usability scale; 6-MWT, 6-min walk test; SEMG, isokinetic protocol in isokinetic dynamometry; 1-RM, 1-repetition maximum; STS, strength training session.*

#### **Table 6.**

*General overview of papers focused on rehabilitation with virtual reality and laser therapy in sarcopenia.*

#### *3.1.2.2 Electrostimulation included whole-body vibration*

It is well-known, from previous studies, that electrostimulation can favor the increase of muscle fibers thus improving MS, MQ, and PP and today confirmed in different works [51]. In 2016, Wittman et al. [52] and then Klemmer et al. [53–55] evaluated the parameters linked to sarcopenia and the WB-EMS effects, according to sex: the FORMOsA trial was conducted on women and the FranSO trial was conducted on men (**Table 7**).

The FORMOsA study concluded that the WB-EMS did not improve MS or PP nor decrease the fat mass, compared to the conventional physical activity [52], but it improved muscle mass. For this reason, it is advisable to use it in cases where the patient is unable to perform conventional resistance training [52, 53]. The FranSO study, on the other hand, showed that in men WB-EMS succeeded in increasing muscle mass and lowering fat mass (in sarcopenic obesity), confirming its use in the case of older people unable to move or unmotivated [54, 55].

To understand the effects of EMS intervention, Nishikawa et al. [56] made three measurements over a period of 12 weeks; then the results were compared with SEMG. Although their conclusions were closely related to a short group of individuals with the locomotive syndrome, the results suggested that EMS was able to increase MS and MQ. However, further studies would have to be performed [56] to obtain more conclusive results.

In the article by Jandova et al. [57], the EMS activity was completed in lumbar multifidus (LM) and vastus lateralis (VL). The results suggested an increase in muscle mass and mobility.


#### *Sarcopenia: Technological Advances in Measurement and Rehabilitation DOI: http://dx.doi.org/10.5772/intechopen.101278*


*intermittent whole-body vibration; BPP, bench press power; VJ, vertical jump (height); MAP, mean arterial pressure; TGs, triglycerides; FPG, fasting plasma glucose; HDL-C, high-density lipoprotein cholesterol; WPS, whey protein supplementation; TBF, total body fat mass; TF, trunk fat mass; TAG, triglycerides; HOV, healthy older volunteer; TUG, timed up and go test; FTSST, five times sit-to-stand test; MT, muscle thickness; PA, pennation angle; FL, fiber length; LM, lumbar multifidus; VL, vastus lateralis; VL-CSA, VL cross-sectional area; LM-CSA, LM cross-sectional area; RPW, relative proprioceptive weighting ratio VS, vibratory stimulation.*
