The JUMPFOOD study: additional effect of hydrolyzed collagen and vitamin C to exercise treatment for patellar tendinopathy (jumper’s knee) in athletes—study protocol for a double-blind randomized controlled trial

Table 1 Schematic diagram of the JUMPFOOD study

		V1		V2–V4
	At home by mail or telephone	At the hospital Sports Valley	Start of study	At the hospital Sports Valley Week 0, week 12, and week 24	Online Week 6, week 18, and week 52	During the entire 24 weeks, daily	During the entire 24 weeks, weekly
Handover study information and informed consent	X
Telephone call: discuss questions about participation	X
Signing informed consent	X
Online screening	X
VISA-P	X
Pain map	X
Inclusion questions	X
Hospital screening		X
Physical examination		X
Ultrasound		X
Functional tests		X
Explanation PTLE program		X
Randomization			X
Study measurements				X
Body composition^b				X
Questionnaires^c				X	X^a
Blood sampling				X
Functional tests^d				X
Imaging^e				X
Myoton				X
Compliance (sachets check)				X
Supplement use						X
PTLE program (3 times/week)^f							X
Compliance							X

^aOnly the VISA-P is asked digitally in weeks 6, 18, and 52
^bConsisting of length and body weight measurements and sevenfold sum of skinfolds measurements
^cConsisting of the VISA-P, EQ-5D, MSK, CSI, SARS, OSTRC, and follow-up questions investigating satisfaction, return to sports, pain during activities of daily living, during sports and during the PTLE program, the use of co-interventions, compliance to exercise program and supplement intake, and investigating training load
^dConsisting of the single leg decline squat and measurements of the isometric strength of the quadriceps, hamstrings, and abductors; muscle length; drop jump test; weight-bearing dorsiflexion lunge test; hoptests; and the squat vs countermovement jump
^eConsisting of an ultrasound (grayscale and power Doppler) and UTC, with the ultrasound executed at 0 and 24 weeks and not at 12 weeks
^fPart of usual care

ISSN: 1745-6215