Table 2

Samples, characteristics of interventions and outcome measures of the included studies

Author	Tendon affected	Sample, mean/median age (range); % F	Symptom duration	Interventions	Treatment duration (follow-up)	Adherence to treatment	Outcome measures
Gatz et al37	Achilles.	n=42, mean 49.5 years (21–73 years); 36%.	2–100 months (mean 27.5 months).	Isotonic (eccentric) exercise (n=20). Isotonic (eccentric) exercise + isometric exercise (n=22).	3 months (0, 1 month, 3 months).	100% in first month and around 50% thereafter.	VISA-A (pain, function). AOFAS (pain, function). Likert scale (clinical improvement with treatment). Roles and Maudsley score (clinical improvement with treatment). Tissue elasticity (shear wave elastography).
Clifford et al17	Gluteal.	n=30, mean 59.3 years (24–86 years); 90%.	Mean 23 months.	Isometric exercise (n=15). Isotonic exercise (n=15).	12 weeks (0, 4 weeks, 12 weeks).	70% of isometric group and 58% of isotonic group completed 80% of treatment sessions.	Tendon-specific: VISA-G (pain, function). NPRS 0–10 for pain. EQ-5D-5L (QoL). IPAQ-SF. GROC. PCS. HOOS.
Holden et al22	Patellar.	n=21, mean 26.5 years (18–40 years); 41%.	10–84 months (mean 24 months).	Isometric exercise (n=21). Dynamic (isotonic) exercise (n=21). Same group performed both interventions.	Single session of each intervention.	N/A.	Pain intensity during SLDS (NRS 0–10). Pressure pain thresholds. Patellar tendon thickness (USS).
Vuvan et al34	Wrist extensors.	n=40, mean 48.5 years (?– ? years); 28%.	2–8 months (mean 4 months).	Wait and see (n=19). Isometric exercise (n=21).	8 weeks (0–8 weeks).	87%.	GROC. Tendon-specific: PRTEE (pain, disability). VAS 0–10 for pain. Pain-free grip strength (function). Thermal and pressure pain threshold (nervous system sensitisation).
Dupuis et al31	Rotator cuff.	n=43, mean 38.3 years (18–65 years); 44%.	<6 weeks.	Weeks 0–2: Isometric exercise (n=20). Ice therapy (n=23). Weeks 3–6: Both groups same isotonic exercise programme.	6 weeks (0, 2 weeks, 6 weeks).	Weeks 0–2: exercise group 76% and cryotherapy group 80%. Weeks 3–6: exercise group 40% and cryotherapy group 70%.	USS to measure acromiohumeral distance. Strength (maximum force in shoulder abduction and external rotation). ROM. DASH (functional disability). Tendon-specific: WORC (QoL). BPI (pain 0–10).
Parle et al32	Rotator cuff.	n=20, mean 50 years (20–67 years); 65%.	<12 weeks.	Ice therapy (n=6). Isometric exercise (n=7). Ice therapy plus isometric exercise (n=7).	1 week (0–1 week).	Unclear.	VAS 0–10 for pain. DASH (functional disability). Strength (maximum force in shoulder flexion). Structural integrity (USS).
Rio et al35	Patellar.	n=29, mean 23 years (16–32 years); 7%.	1–120 months (mean 35.8 months).	Isometric exercise (n=13). Isotonic exercise (n=16).	4 weeks (0, daily pre- exercise and postexercise, 4 weeks).	Unclear.	Pain during the SLDS (NRS 0–10) preintervention and postintervention. Tendon-specific: VISA-P (pain, function).
Stasinopoulos and Stasinopoulos33	Wrist extensors.	n=34, mean 43 years ; 56%.	>4 weeks (mean 6 months).	Eccentric exercise (n=11). Eccentric-concentric exercise (n=12). Eccentric-concentric exercise + isometric exercise (n=11).	4 weeks (0, 4 weeks, 8 weeks).	Unclear.	VAS 0–10 for pain. Pain-free grip strength (function). VAS 0–10 for function.
van Ark et al36	Patellar.	n=29, mean 23 years (16–32 years); 7%.	1–120 months (mean 35.8 months).	Isometric exercise (n=13). Isotonic exercise (n=16).	4 weeks (0–4 weeks).	Unclear.	Pain during the SLDS (0–10). Tendon-specific: VISA-P (pain, function).
Rio et al20	Patellar.	n=6, median 27 years (18–40 years); 0%.	Not stated.	Isometric exercise (n=6). Isotonic exercise (n=6). Same group performed both interventions.	Single session of each intervention (0–45 min).	N/A.	Pain during the SLDS (NRS 0–10). Strength (quadriceps MVIC). Measures of corticospinal excitability and inhibition.

The clinical parameters assessed by each questionnaire in the outcome measures are stated in brackets.
AOFAS, American Orthopaedic Foot and Ankle Score; BPI, Brief Pain Inventory; DASH, Disabilities of the Arm, Shoulder and Hand; EQ-5D-5L, EuroQoL 5 Dimensions 5 Level Index; GROC, Global Rating of Change; HOOS, Hip Disability and Osteoarthritis Outcome Score; IPAQ-SF, International Physical Activity Questionnaire-Short Form; MVIC, maximum voluntary isometric contraction; N/A, not applicable; NPRS, Numeric Pain Rating Scale; NRS, Numeric Rating Scale; PCS, Pain Catastrophising Scale; PRTEE, Patient-Rated Tennis Elbow Evaluation; QoL, quality of life; ROM, range of movement; SLDS, single leg decline squat; USS, ultrasound scan; VAS, Visual Analogue Scale; VISA-A, Victorian Institute of Sport Assessment-Achilles tendon; VISA-G, Victorian Institute of Sport Assessment-gluteal tendons; VISA-P, Victorian Institute of Sport Assessment-patellar tendon; ; WORC, Western Ontario Rotator Cuff Index.