Table of contents:
What is Physical therapy?
Physical therapy or physiotherapy is defined as the field of medicine that deals with the prevention, intervention, and diagnosis of several disorders/deformities, with the overall goal of enhancing human movements and performance. It is the art of healing and the science of rehabilitation. There are many medical fields concerned with the healing of mankind but, physical therapy is the only one in which you dive deep into the feelings and emotions of patients and interact with them in such a gentle way that any disorder or disease can be rectified. A physiotherapist not only prevents and cures the disease but in addition, he also enhances the normal functioning of human body parts. Everything you need to know regarding old and modern physiotherapy is provided below:
History of Physical therapy?
Physical therapy has ancient origins. Thousands of years ago, sick and disabled people were treated in a variety of ways: air, water, heat, cold, electricity, and light. This particular field of medicine has a long history but has historically been largely unstudied. A brief review of the relevant literature in the field of medical history over the past 20 years reveals that the development of body medicine as a health professional over the last 200 years has rarely been the subject of scientific study. Before that, things weren’t so good. Glenn and Arnold noted that sociologists and historians have neglected this area of concern.
History of physiotherapy: Physical education teacher and physician Johan Georg Mezger (1838–1909) who frequently treated royalty in the Amstel Hotel (Source: Kostelijk PJ. Dr. Johann Georg Mezger—1838–1909—en Zijn Tijd. [Dutch for: Dr. Johann Georg Mezger—1838–1909 and His Time]. Leiden, the Netherlands: Universitaire Pers, 1971).  Owner: Figure – PMC (nih.gov)
In the late 19th century, in an era of increased specialization in the medical field, terms such as “physiotherapy”, “physiotherapy”, and “physiotherapy” were used to categorize movements in various healing methods like manipulations and massage (also called mechanotherapy). In 1942, an act was passed in which the emerged division of labor in this field was confirmed, while control over diagnosis and treatment would remain an unsettled issue until new legislation came about in the 1990s. 
Modern Physical therapy?
Everything has advanced with the development of science and medicine in the modern era. Similarly, several different technologies are also introduced in physiotherapy. Recently, new techniques of rehabilitation have proliferated in hopes of improving outcomes, increasing patient compliance and safety, and restoring exercise capacity. With technological advances, post-injury rehabilitation is harnessing the ability to push boundaries in hopes of accelerating recovery, standardizing treatment, closer release to the state of previous injuries, and reducing disability. Some of the Modern physical therapy techniques to diagnose and treat disorders/deformities are mentioned below: 
1: BFR Training
The technique involving Low-intensity exercises combined with the restriction of blood flow to give results similar to high-intensity exercises is called Blood flow restriction (BFR) training.
To see effective results, the patient must perform high-intensity exercises but due to injuries and disorders, the patient is unable to perform this activity. Therefore, there was a need to develop a technique that allows low-intensity training to produce the results of high-intensity training.
2: Force plates
Force plates are used to measure force production. Force plate manufacturers have created affordable hardware and software solutions that analyze and report performance with dual plates. Functional testing batteries are used to compare their performance in a clinical setting. These protocols are easy to analyze without the aid of a biomechanist. Monitoring tools and outcome measures can be used to assess athletes’ responses to training. 
3: Exoskeletons for lower limb trauma
Exoskeletons are certainly made for HELET i.e., High energy lower extremity trauma. To amputate or save limbs after HELET is a controversial matter. To deal with this thing, exoskeletons were made. During military operations, the soldiers were unable to stand for a long time and to perform plantarflexion during active duty. To combat this, a custom ankle-foot orthosis called the intrepid dynamic exoskeletal orthosis (IDEO) was developed. It utilizes a footplate with a rollover design to allow engagement from heel strike to toe-off to load posterior struts that allow plantarflexion easily. 
4: Motion capture & Video biofeedback
The general public is now able to use video motion capture tools. Machine learning and high-speed video are used to create models that can be used in real-time. Patient perception of motion signatures can be enhanced with video or motion capture. A live motion capture display can be used to modify or correct patient movements. 
5: Musculoskeletal Ultrasound
Ultrasound is an ideal musculoskeletal imaging modality in the outpatient setting due to its high resolution, non-invasive nature, low cost, and ready availability . Traditionally considered a diagnostic tool, advances in technology have led to new applications with the potential to guide loading prescriptions during the rehabilitation of soft tissue injuries . It’s possible to see the location and severity of soft tissue injuries.
6: Instrumented Insoles
Instrumented insoles such as Novel Loadsol (Novel.de) are inexpensively available, can provide real-time data to Android or iOS devices, and provide various forms of biofeedback (tactile, auditory, visual) to the user. This technique has been used to improve movement quality, increase lower extremity loading, improve compliance with weight limits, and positively alter gait mechanics. 
7: Joint Arthroplasty: pre- and post-care tools
Although total joint replacement is generally considered an effective surgery, it can be difficult to accurately predict outcomes and recovery for individuals within a heterogeneous population. As such, there is a growing need to develop patient-specific information on outcomes and recovery for TJA (Total Joint Arthroplasty) and other elective orthopedic surgical procedures. The ACHE tool uses regression modeling to determine if a patient will have a successful outcome after TJA. 
8: Personalized Reference Charts
Personalized reference charts (PRCs) are created using “curve matching” which has been utilized to improve the predictive capability of pediatric growth charts. Just as growth charts can be used to predict and monitor an infant’s growth based on the historical data of similar children, PRCs can be used to predict and monitor patient outcomes based on the recovery data of previous similar patients. Knee Range of Motion (ROM) and Timed Up and Go (TUG) are good examples of how PRC impacts patient-centered care. 
Physical therapy has evolved over the years. Passive treatments such as massage and heat therapy have been at the forefront in the past. These treatments were aimed at relieving pain and restoring mobility but were not very effective in treating the underlying cause of the patient’s condition. But today’s physiotherapy is more dynamic and effective than the old one. Moreover, the disorder or diseases related to physical therapy can now be easily diagnosed and treated using modern technologies.
Terlouw T. J. (2007). Roots of Physical Medicine, Physical Therapy, and Mechanotherapy in the Netherlands in the 19 Century: A Disputed Area within the Healthcare Domain. The Journal of manual & manipulative therapy, 15(2), E23–E41. https://doi.org/10.1179/jmt.2007.15.2.23E
Owens, J. G., Rauzi, M. R., Kittelson, A., Graber, J., Bade, M. J., Johnson, J., & Nabhan, D. (2020). How New Technology Is Improving Physical Therapy. Current reviews in musculoskeletal medicine, 13(2), 200–211. https://doi.org/10.1007/s12178-020-09610-6
Deimel GW, Jelsing EJ, Hall MM. Musculoskeletal ultrasound in physical medicine and rehabilitation. Curr Phys Med Rehabil Rep. 2013;1:38–47. doi: 10.1007/s40141-012-0003-9. [CrossRef] [Google Scholar] [Ref list
Hall MM. Return to play after thigh muscle injury: utility of serial ultrasound in guiding clinical progression. Cur Sports Med Rep. 2018;17:296–301. doi: 10.1249/JSR.0000000000000516. [PubMed] [CrossRef] [Google Scholar] [Ref list
Price A, Smith J, Dakin H, Kang S, Eibich P, Cook J, et al. The arthroplasty candidacy help engine tool to select candidates for hip and knee replacement surgery: development and economic modelling. Health Technol Assess. 2019;23(32):1–216. doi: 10.3310/hta23320. [PMC free article] [PubMed] [CrossRef] [Google Scholar] [Ref list
Van Buuren S. Curve matching: a data-driven technique to improve individual prediction of childhood growth. Ann Nutr Metab. 2014;65(2–3):227–233. doi: 10.1159/000365398. [PubMed] [CrossRef] [Google Scholar] [Ref list]