Table 2.
Normalized muscle mass (MM), muscle belly length (ML), fascicle length (L F), moment arm (r m), maximum isometric force (F max), and instantaneous power (P inst) for muscles from adult and juvenile rabbits
| Muscle | Age | MM (g kg−1) | ML (cm/MM0.33) | L F (cm/MM0.33) | r m (cm/MM0.33) | PCSA (cm2/MM0.67) | F max (N kg−1) | P inst a (W kg−1) |
|---|---|---|---|---|---|---|---|---|
| PMN | A | 1.26 (0.88–1.56) | 5.58 (3.44–6.94) | 3.44 (1.62–5.80) | 0.53 (0.43–0.76) | 0.31 (0.17–0.44) | 9.42 (4.26–14.9) | 0.18 (0.15–0.28) |
| J | 0.81 (0.41–1.57) | 6.24 (4.93–7.76) | 4.16 (1.43–6.48) | 1.31 (0.99–1.80) | 0.25 (0.16–0.46) | 9.79 (7.08–17.4) | 0.15 (0.09–0.28) | |
| LD | A | 42.4 (37.9–47.2) | 5.49 (4.43–6.42) | 1.20 (0.32–2.31) | – | 0.98 (0.46–1.78) | 291 (154–565) | 5.81 (0.24–7.62) |
| J | 26.7 (23.4–38.3) | 6.05 (5.21–6.77) | 1.59 (0.98–2.52) | – | 0.58 (0.44–0.80) | 236 (184–283) | 4.50 (3.77–6.26) | |
| SS | A | 4.45 (3.60–6.29) | 11.3 (9.02–13.0) | 1.19 (0.46–1.92) | – | 0.78 (0.54–1.22) | 66.7 (39.1–84.2) | 0.67 (0.60–1.03) |
| J | 3.14 (1.54–4.63) | 12.4 (10.8–13.6) | 0.79 (0.38–1.66) | – | 1.35 (0.64–1.68) | 128 (49.6–175) | 0.50 (0.26–0.66) | |
| PMJ | A | 5.70 (2.72–7.38) | 6.69 (5.51–7.62) | 3.61 (1.64–6.07) | 0.50 (0.27–0.82) | 0.26 (0.19–0.35) | 23.9 (15.0–40.0) | 0.96 (0.47–1.23) |
| J | 4.32 (3.25–7.01) | 7.33 (5.38–8.67) | 4.62 (2.09–6.90) | 0.71 (0.30–0.96) | 0.20 (0.15–0.31) | 24.6 (16.6–36.9) | 0.78 (0.58–1.20) | |
| GLS | A | 0.84 (0.55–1.32) | 3.13 (2.29–3.88) | 2.34 (1.50–3.73) | 0.61 (0.23–1.07) | 0.41 (0.31–0.50) | 9.90 (7.20–13.0) | 0.14 (0.10–0.23) |
| J | 1.52 (0.60–2.50) | 2.57 (1.37–3.29) | 2.24 (1.09–3.45) | 0.62 (0.31–1.27) | 0.48 (0.31–0.83) | 30.1 (10.8–78.4) | 0.27 (0.11–0.44) | |
| GLM | A | 2.44 (1.06–3.89) | 2.36 (1.80–2.74) | 2.04 (1.03–3.31) | 0.80 (0.54–1.39) | 0.52 (0.39–0.79) | 25.1 (20.1–33.7) | 0.45 (0.19–0.74) |
| J | 1.88 (0.61–2.92) | 2.62 (1.87–4.48) | 2.09 (1.18–2.88) | 0.72 (0.41–1.19) | 0.48 (0.36–0.65) | 33.6 (8.74–127) | 0.40 (0.05–1.59) | |
| GLP | A | 3.30 (1.67–6.69) | 2.34 (1.66–3.10) | 1.94 (0.86–2.95) | 0.61 (0.46–0.82) | 0.53 (0.35–0.77) | 35.7 (15.4–72.6) | 0.61 (0.33–1.19) |
| J | 1.67 (0.52–4.67) | 2.52 (1.97–3.22) | 1.83 (1.02–3.32) | 0.61 (0.40–0.85) | 0.53 (0.34–71) | 30.3 (11.2–75.6) | 0.31 (0.08–0.88) | |
| BFP | A | 8.57 (5.23–9.66) | 3.94 (3.34–4.67) | 2.95 (1.47–4.43) |
1.15 (0.52–1.62)h
0.56 (0.26–1.37)k |
0.33 (0.24–0.46) | 40.6 (27.3–56.7) | 1.60 (1.40–1.86) |
| J | 6.21 (2.78–8.98) | 4.06 (3.61–4.53) | 3.25 (1.43–3.97) |
1.20 (0.91–1.66)h
0.81 (0.46–1.24)k |
0.29 (0.25–0.35) | 45.5 (8.36–128) | 1.28 (0.15–4.32) | |
| BFV | A | 7.84 (6.04–9.88) | 4.26 (3.37–5.11) | 2.63 (0.66–4.83) |
0.56 (0.30–0.88)h
0.46 (0.25–0.91)k |
0.36 (0.22–0.53) | 40.2 (20.3–56.3) | 1.30 (0.98–1.56) |
| J | 5.82 (3.99–7.85) | 4.56 (3.78–5.40) | 2.94 (0.48–4.26) |
0.70 (0.44–1.03)h
0.76 (0.49–0.99)k |
0.31 (0.23–0.52) | 45.1 (9.11–107) | 1.10 (0.20–3.46) | |
| SM | A | 4.62 (3.28–6.12) | 4.23 (3.23–5.08) | 3.12 (1.82–4.63) |
1.45 (1.17–1.77)h
1.56 (0.94–2.08)k |
0.32 (0.21–0.44) | 25.4 (18.0–34.2) | 0.84 (0.66–1.08) |
| J | 4.26 (2.58–9.55) | 4.22 (3.44–4.86) | 3.33 (2.06–4.26) |
1.71 (1.16–2.13)h
1.36 (0.89–1.72)k |
0.29 (0.23–0.36) | 33.6 (7.90–115) | 0.79 (0.14–2.82) | |
| ST | A | 0.64 (0.38–0.81) | 5.02 (4.59–5.41) | 3.42 (2.40–4.61) |
3.09 (2.79–3.40)h
0.85 (0.39–1.72)k |
0.29 (0.22–0.36) | 6.33 (4.93–7.74) | 0.12 (0.10–0.13) |
| J | 0.39 (0.23–0.76) | 4.96 (4.49–5.56) | 3.43 (2.27–4.80) |
3.27 (2.64–3.90)h
0.77 (0.41–1.35)k |
0.28 (0.21–0.37) | 7.2 (4.16–12.6) | 0.07 (0.05–0.11) | |
| ADD | A | 10.7 (4.60–16.4) | 3.58 (3.01–4.75) | 2.78 (0.89–4.18) |
0.86 (0.71–1.07)h
0.40 (0.11–1.24)k |
0.35 (0.29–0.44) | 48.3 (21.2–67.0) | 1.89 (0.18–3.12) |
| J | 9.60 (6.14–12.6) | 3.24 (2.42–4.12) | 2.42 (1.29–3.30) |
0.95 (0.65–1.19)h
0.34 (0.14–0.62)k |
0.39 (0.34–0.43) | 81.2 (58.6–102) | 1.71 (1.09–2.24) | |
| GRC | A | 1.93 (0.76–2.51) | 5.19 (4.87–5.52) | 3.66 (3.22–4.11) | 1.30 (1.30–1.30) | 0.26 (0.25–0.26) | 12.3 (10.6–14.0) | 0.37 (0.33–0.42) |
| J | 2.19 (1.41–4.76) | 4.31 (3.41–5.50) | 2.85 (1.35–3.99) | 0.62 (0.62–0.62) | 0.38 (0.26–0.51) | 1.20 (0.91–1.49) | 0.26 (0.25–0.27) | |
| TFL | A | 1.33 (0.77–1.71) | 2.73 (1.52–4.17) | 2.06 (0.79–4.47) | 0.72 (0.56–1.04) | 0.55 (0.26–0.85) | 12.8 (6.65–20.8) | 0.18 (0.14–0.25) |
| J | 0.78 (0.55–1.08) | 3.45 (2.18–4.67) | 2.89 (1.21–4.66) | 0.74 (0.47–1.00) | 0.38 (0.20–0.53) | 16.1 (9.25–21.1) | 0.15 (0.12–0.19) | |
| SRT | A | 4.42 (2.86–5.59) | 4.48 (4.13–5.05) | 2.88 (1.07–4.60) |
1.72 (0.86–2.35)h
0.59 (0.29–0.97)k |
0.34 (0.24–0.43) | 25.5 (17.2–37.9) | 0.75 (0.51–0.97) |
| J | 3.15 (2.08–4.74) | 4.97 (3.66–6.13) | 3.59 (1.46–5.88) |
1.89 (0.78–2.51)h
0.78 (0.50–1.16)k |
0.28 (0.17–0.49) | 28.0 (14.5–50.5) | 0.56 (0.37–0.81) | |
| RF | A | 2.61 (0.91–3.87) | 4.78 (4.49–5.35) | 1.40 (0.31–2.41) |
0.71 (0.47–1.12)h
0.79 (0.35–1.43)k |
0.67 (0.44–1.09) | 37.5 (18.3–70.7) | 0.44 (0.20–0.64) |
| J | 1.79 (0.68–5.43) | 5.11 (3.50–6.29) | 1.77 (0.91–2.60) |
0.62 (0.48–0.92)h
1.28 (0.68–2.05)k |
0.51 (0.39–0.80) | 30.8 (10.3–72.5) | 0.27 (0.04–0.55) | |
| VL | A | 6.76 (4.18–8.16) | 3.52 (3.03–4.07) | 1.96 (0.84–3.51) | 0.57 (0.29–0.83) | 0.49 (0.27–0.73) | 50.8 (28.1–70.9) | 1.13 (0.96–1.24) |
| J | 5.63 (3.57–8.31) | 3.60 (3.27–3.85) | 1.97 (0.80–3.51) | 0.91 (0.44–1.22) | 0.47 (0.29–0.64) | 66.6 (24.8–151) | 1.08 (0.26–3.52) | |
| VM | A | 2.31 (1.47–3.08) | 4.87 (3.75–6.19) | 2.02 (0.64–4.59) | 0.52 (0.27–1.01) | 0.52 (0.25–0.87) | 25.8 (11.6–38.4) | 0.33 (0.08–0.51) |
| J | 1.84 (0.94–3.77) | 5.06 (3.94–7.20) | 2.60 (0.84–5.69) | 0.88 (0.67–1.26) | 0.44 (0.17–0.73) | 30.1 (7.92–54.4) | 0.31 (0.16–0.62) | |
| VI | A | 1.99 (0.99–2.91) | 5.49 (4.65–6.79) | 2.58 (0.80–4.77) | 0.63 (0.33–0.95) | 0.43 (0.23–0.89) | 18.9 (8.52–43.9) | 0.29 (0.07–0.50) |
| J | 1.56 (0.85–2.46) | 5.15 (4.02–6.04) | 2.51 (0.99–5.12) | 0.93 (0.57–1.57) | 0.42 (0.19–0.81) | 26.5 (9.03–66.6) | 0.27 (0.14–0.43) | |
| LG | A | 2.68 (1.26–5.40) | 4.08 (3.18–5.64) | 1.48 (0.27–5.62) |
0.80 (0.63–1.16)k
0.85 (0.72–1.14)a |
0.90 (0.28–2.29) | 55.7 (12.5–195) | 0.44 (0.32–0.80) |
| J | 2.04 (0.76–5.44) | 4.17 (3.01–5.32) | 1.47 (0.61–3.28) |
0.81 (0.48–1.00)k
1.10 (0.88–1.38)a |
0.64 (0.33–1.07) | 43.3 (12.8–128) | 0.31 (0.06–0.88) | |
| MG | A | 3.39 (1.39–6.43) | 3.87 (3.06–4.80) | 1.37 (0.25–3.82) |
0.74 (0.66–0.91)k
0.74 (0.61–0.80)a |
1.00 (0.26–2.08) | 71.4 (13.4–201) | 0.59 (0.33–0.88) |
| J | 3.27 (1.50–5.33) | 3.63 (3.01–4.51) | 1.30 (0.19–3.74) |
0.65 (0.50–0.89)k
0.88 (0.68–1.17)a |
0.91 (0.28–1.67) | 110 (21.4–560) | 0.64 (0.13–2.43) | |
| SOL | A | 1.98 (1.12–2.89) | 4.86 (3.89–5.69) | 1.31 (0.38–3.67) | 0.68 (0.38–0.83) | 0.97 (0.31–1.68) | 46.7 (16.0–82.7) | 0.23 (0.10–0.53) |
| J | 0.95 (0.29–2.20) | 5.41 (4.10–7.60) | 2.06 (0.46–6.74) | 0.86 (0.36–1.72) | 0.67 (0.16–1.43) | 28.8 (3.34–72.7) | 0.17 (0.04–0.68) | |
| FDS | A | 0.60 (0.42–0.95) | 6.61 (6.08–7.08) | 1.98 (0.63–5.02) |
0.82 (0.49–1.13)k
1.13 (0.86–1.37)a |
0.58 (0.21–1.16) | 10.9 (5.83–17.2) | 0.10 (0.07–0.16) |
| J | 1.75 (0.97–2.92) | 4.39 (3.98–4.88) | 2.25 (0.70–4.50) |
0.68 (0.37–0.84)k
0.93 (0.72–1.03)a |
0.42 (0.26–0.64) | 31.0 (14.8–45.3) | 0.32 (0.21–0.51) | |
| FDP + TCD | A | 1.92 (1.17–2.91) | 4.50 (3.60–5.37) | 3.21 (0.74–5.16) | 0.44 (0.38–0.54) | 0.33 (0.26–0.54) | 14.0 (9.90–19.6) | 0.34 (0.21–0.51) |
| J | 1.33 (0.95–2.38) | 4.91 (4.06–6.21) | 2.65 (0.64–4.39) | 0.47 (0.33–0.66) | 0.41 (0.27–0.66) | 22.3 (12.4–41.0) | 0.23 (0.16–0.39) |
Values are mean (range).
Muscle abbreviations listed in text (Methods) and Table S2.
a
Estimates of physiological capacity based on a published value of 6.3 FL s−1 for rabbit m. psoas major.
h, measured at hip joint; k, measured at knee joint; a, measured at ankle joint.
Fascicle length, r m, and PCSA are size‐scaled to muscle mass (MM) assuming isometric scaling for body mass.
Muscle mass, force, and instantaneous power all normalized to body mass in kg.