Table 5.

The biomarker changes from baseline to post-bed-rest

Study	Duration (Days)	Group	Bone formation markers			Bone resorption markers			Other key markers
			NTX	DPD	PYD	BSAP	Total ALP	OCN	Urine Calcium	Serum Calcium	PTH	1,25(OH)2 Vit D	25(OH) Vit D	Creatinine
Shackelford5	119 days	CON	↑*	↑*	↑*	↓	↑	↑	x	↑	↓	↓*	↑	x
		RVE	↑*	↑*	↑*	↑*^	↑*^	↑*^	x	↓*	↓	↑^	↑	x
Rittweger30	90 days	CON	x	↑*	↑*	x	↑**	x	x	=	=	x	x	x
		FW	x	↑*	↑*	x	↑**	x	x	=	=	x	x	x
Smith32	60 days	CON	↑	=	x	↑	↑	=	=	↑	↓	↓	↓*	x
		LBNP TM + RE	↑	↑	x	↑	↑*^	↑	↓	↓	↓	↓	↓*	x
Zwart31	30 days	CON	↑**	↑**	↑**	↓	↓	↓	↑	↓**	↓	↓	↓	↑*
		LBNP TM	↑**	↑**	↑**	↓	↓	↑	↓	↓**	↓	↓	=	↑*
Cavanagh28	84 Days	CON	↑*	x	x	↑	x	x	↑	x	x	x	x	↓
		ZLS	↑*	x	x	↑	x	x	↓	x	x	x	x	↓

The biomarker changes from baseline to post-bed-rest. ↓ decrease in levels, ↑ increase in levels, X no data, = no change

NTX n-telopeptide, DPD deoxypyridinoline, PYD pyridinium cross-links, total ALP total alkaline phosphatase, BASP bone specific alkaline phosphatase, OCN osteocalcinin, PTH Parathyroid hormone, CON control group, RVE resistive vibration exercise, FW flywheel, LBNP TM lower body negative pressure treadmill, ZLS zero-gravity locomotion simulator

*Significant from baseline p < 0.05, **significant from baseline p < 0.01 (Cavanagh²⁸ used a two sample t-test. Zwart³¹ and Smith³² used post hoc testing with the Bonferroni method. Rittweger³⁰ and Shackelford⁵ used analysis of variance), ^significant between exercise and control groups p < 0.05 (Cavanagh²⁸ used two sample t-test. All other studies used analysis of variance)