CTGF mRNA normalized to tissue weight, presented as fold changes relative to the mean of all control values, in Achilles tendon (A and C) and gastrocnemius muscle (B and D) subjected to concentric (CON), eccentric (ECC) and isometric (ISO) training (grey bars) versus contralateral controls (white bars). Levels of mRNA were measured with real-time RT-PCR (A and B) and Northern blotting (C and D). Values are geometric means ±s.e.m.A and C, in tendon, no changes were seen in CTGF mRNA levels (P > 0.05). B and D, in muscle, CTGF increased in response to ECC and ISO (*P < 0.05, **P < 0.01, ***P < 0.001), while no effect was seen of CON (P > 0.05).