Table 3: A comparison of animal and in vitro studies indicating the positive effect of physiological joint loading in articular cartilage.

Type of loadRegimenModel systemMajor effectReference

Running exercise6 to 12 km/dayHamsterIncreased proteoglycan content[26]
Running exercise15 km over 28 daysRat OA induced by ACLTReduced apoptosis and chondral erosions[50]
Running exerciseVaried age, 15 months exerciseRabbitImproved collagen organisation in young and reversed OA in older animals[54]
Increased loadingIncreased loading following 8 weeks of splintingRabbitIncreased maturation of tissue and increased collagen content[55]
Conditioning exerciseIncreased workload by 30%FoalsReduced cartilage degeneration index[56]
Running exercise4 km/day, uphill, 15 weeksBeagle dogsIncreased proteoglycan content and cartilage thickness[53]
Cyclic pressure-induced strain0.3 Hz, 6 hoursHuman and monolayerIncreased aggrecan gene expression[58]
Hydrostatic pressure5 and 10 MPa at 1 Hz for durations of 4 h per day for 4 daysHuman monolayerIncreased aggrecan and collagen type II gene expression[59]
Dynamic compression3% at 0.01 to 1 Hz, 43 daysBovine and agaroseIncreased proteoglycan and collagen synthesis[63]
Dynamic compression15%, 1 Hz, 48 hoursBovine and agaroseIncreased cell proliferation and proteoglycan synthesis and reduced nitrite release[60, 61]
Dynamic compression10% at 1 Hz, 3  ×  1 hr on, 1 hr off, 5 days/week for 21 daysBovine and agaroseIncreased equilibrium aggregate modulus, sGAG and collagen synthesis[62]
Dynamic compression1 MPa, repeated 2 and 4 sec, 1.5 hourBovine and explantsIncreased proteoglycan synthesis[64]
Cyclic compression1 MPa, 0.5 Hz, 3 daysBovine and explantsIncreased proteoglycan synthesis[70]