TY  - JOUR
A1  - Khajooei, Mina
A1  - Lin, Chiao-I
A1  - Mayer, Frank
A1  - Mueller, Steffen
T1  - Muscle activity and strength in maximum isokinetic legpress testing with unstable footplates in active individuals
JF  - Isokinetics and exercise science : official journal of the European Isokinetic Society
N2  - BACKGROUND: Compensating unstable situations is an important functional capability to maintain joint stability, to compensate perturbations and to prevent (re-)injury. Therefore, reduced maximum strength and altered neuromuscular activity are expected by inducing instability to load test situations. Possible effects are not clear for induced instability during maximum legpress tests in healthy individuals. OBJECTIVE: To compare isokinetic legpress (LP) strength and lower-leg muscle activity using stable (S) and unstable (UN) footplates. METHODS: 16 males (28 +/- 4 yrs, 179 +/- 7 cm, 75 +/- 8 kg) performed five maximum LP in concentric (CON) and eccentric (ECC) mode. The maximum force (Fmax) and muscle activity were measured under conditions of S and UN footplates. The tested muscles comprised of the tibialis anterior (TA), peroneus longus (PL) and soleus (SOL) and their activity were quantified against the MVIC of each muscle respectively. RESULTS: The main finding revealed a significant reduction in Fmax under UN condition: 11.9 +/- 11.3% in CON and 23.5 +/- 47.8% in ECC (P < 0.05). Significant findings were also noted regarding the RMS derived values of the EMG of PL and TA. CONCLUSION: Unstable LP reduced force generation and increased the activity of PL and TA muscles which confirmed greater neuromuscular effort to compensate instability. This may have some implications for resistance testing and training coupled with an unstable base in the prevention and rehabilitation of injury to the neuromusculoskeletal system.
KW  - Tibialis anterior
KW  - peroneus longus
KW  - soleus
KW  - instability
Y1  - 2019
U6  - https://doi.org/10.3233/IES-182206
SN  - 0959-3020
SN  - 1878-5913
VL  - 27
IS  - 3
SP  - 177
EP  - 183
PB  - IOS Press
CY  - Amsterdam
ER  -