## 3 Results
### Key Findings
#### 3.3.1 Midportion Achilles Tendinopathy
The patient needs to stand on a higher base on the forefoot while the ankle joint is in plantar flexion The patient then eccentrically loads the injured leg by lowering the heel level with the knee straightened or bent, followed by concentrically loading the plantar flexors of both legs. The HECT protocol can be aggravated by using extra loads (an extra-loaded backpack or machine). The HECT protocol is relatively easy to execute, even at home [27]. There are some modifications to the classic HECT protocol with customized pain (i.e., \"do-as-tolerated\" protocol) [14; 16; 33; 75; 77] that is achieved by limiting the range of motion (a patient eccentrically loads the plantar flexors of the ankle only to the floor level/obstacle) [14] or adjusting the number of sessions, series, or repetitions [33]. Both classic and \"do-as-tolerated\" HECT were found to significantly decrease pain, improve function, and cause a significant improvement in patient satisfaction compared to the baseline [33; 77]. Modified HECT that was executed 3 x/week caused a greater pain decrease than classic HECT that was executed 2 x/day [33; 77]. Similarly, the same duration, modified HECT protocol (with 3 sessions/week) caused greater function improvement than the classic HECT protocol, but the difference was statistically unsignificant [33]. On the other hand, [PERSON] et al. [33] did not report any difference between the mentioned protocols in the case of patient satisfaction improvement. The mean improvement in the VISA-A score between the pre- and post-test results, after finishing either a 12-week classic HECT or the same duration, modified HECT that gradually increased the number of series within a session, was around 74% [77]. Similarly, [PERSON] et al. [33] reported that the execution of a 12-week HECT protocol 3 x/week decreased pain by 35.6 points on a 100-point scale (when compared to the baseline), which was 11.7 points greater compared to classic HECT. Higher loading magnitudes caused greater tendon stiffness and a greater increase in tendon cross-sectional area compared to lower loading magnitudes [33]. ECC exercise with the gradually addition of an extra load additionally decreased pain compared to normal ECC exercise [51]. Unlike ECC contraction, ISOM contraction occurs when the muscle does not change its length during contraction [78]. A single session of ISOM exercise of the plantar flexor muscle that consisted of 10 repetitions with an intermediate break of 60 s largely decreased the Achilles tendon cross-sectional area (with standardized mean difference (SMD) of \(-1.01\)) and Achilles tendon volume (with SMD of \(-1.24\)) [31]. It caused small changes in Achilles tendon length (with SMD of 0.27) [31]. A single session of ECC exercise caused a small-to-moderate increase in the Achilles tendon volume (with SMD of 0.41) [31] and instant changes in cortical inhibition and tendon pain [34], while longer execution of the ECC exercise protocol resulted in a small-to-moderate decrease in Achilles tendon volume (with SMD of \(-0.46\)), which was observed as long as 4 years after the protocol for treating MAT ended (SMD = \(-0.15\)) [31]. ISOT contraction includes both ECC and CON contractions [78]. During the entire range of motion, the force produced by the muscle stays unchanged and is greater than the external resistance/load [78]. The most frequently used ISOM exercises for treating MAT were HSR (heavy slow resistance) exercise [55; 70], the Stanish and Curwin protocol [33; 34], and the combined ISOT and ECC exercise, called the Silbernagel combined protocol [33; 34; 56] (Table S2). Although ECC exercise (i.e., HECT) caused a greater pain decrease (especially while running or heel raising) and function improvement compared to wait-and-see or traditional physiotherapy, HECT caused a similar pain decrease and function improvement as HSR exercise did [55; 70]. The biggest difference in results caused by either ECC exercise or HSR exercise was connected to the improvement in patient satisfaction [55].