Table 1.

Study characteristics, results, and Downs and Black scores.

Author, Year	DB Score	Subjects	Primary Variable(s)	Experimental Protocol	Results	Conclusions
Bailey et al., 2003	13	• 24 male cyclists • 10 with knee pain history • Experienced • 28.0 + 8.4 yrs	• Kinematics: coronal/ sagittal hip, knee, ankle	• Conditions: 90 rpm, 200 ± 10W • Cycle: Own cycles on trainer	• Cyclists with knee pain had ↑ dorsiflexion & knee valgus. • No differences in knee flexion angle with & without knee pain. • Anterior knee pain seen when knee extensors active.	• More medial knee position (valgus) may disrupt knee extensor mechanism, leading to pain. • ↑ dorsiflexion with knee injury history possibly unrelated to pain as difference seen along with knee flexor moment.
Barrett et al., 2011	10	• 15 cyclists (12 male) • No injury • Experienced • 19-44 yrs	• Kinetics: 2D joint powers at hip, knee, ankle	• Conditions: 5 different crank lengths, 2 cadences (“optimized” & 120 rpm), 3sec maximal efforts. • Cycle: Isokinetic ergometer	• Crank length had no effects on power at optimized cadence. • At 120 rpm, crank length impacted hip & knee powers when comparing shortest & longest (150 & 190 mm) with ↑ at 150 mm.	• When cadence is accounted for, crank length does not impact joint powers.
Barrett et al., 2016	10	• 15 cyclists (12 male) • No injury • Trained • 19-44 yrs	• Kinetics: Sagittal plane forces, 2D muscle moments, joint powers at hip, knee, ankle	• Conditions: 5 different crank lengths, 2 cadences (“optimized” & 120 rpm), 3sec maximal efforts. • Cycle: Isokinetic ergometer	• ↑ Knee & hip ROM with ↑ cadence & crank length. • ↓ Knee extension moments & power and ↑ hip extension power with ↑ crank length.	• Powers most impacted by crank length.
Bini et al., 2013	9	• 21 male cyclists • No injury • Competitive • 28 ± 7 yrs	• Kinematics: knee flexion • Kinetics (2D): Patellofemoral compressive & tibiofemoral compressive/ shear forces	• Conditions: 1 min; 90 rpm; max power output; preferred, forward and backward saddle positions (self-selected to simulate time trial or hill climbing). • Cycle: Own cycles on trainer	• ↓ Tibiofemoral anterior shear forces in forward saddle position. • ↑ Knee flexion angle comparing forward to backward saddle positions. • Neither position affected patellofemoral & tibiofemoral compressive forces.	• Tibiofemoral anterior shear forces more sensitive to knee angle. • Larger differences in knee flexion angle across conditions may be needed to affect compressive forces.
Bini et al., 2014	9	• 24 cyclists (12 road, 12 triathlon) • No injury • Competitive • 36 ± 14 yrs (road), 42 ± 8 yrs (tri)	• Kinematics: sagittal hip, knee, ankle • Kinetics (2D): pedal forces, net joint moments (hip, knee, ankle), pedal force effectiveness	• Conditions: Four 2min trials, submax effort, 4 saddle heights: 1) preferred, 2) low (-10 ° change in knee flexion angle at bottom dead center), 3) high (+10 ° change) 4) “optimal saddle height” (25 ° knee flexion). • Cycle: Stationary ergometer	• ↑ Force effectiveness optimal saddle height (road cyclists). • ↓ Ankle ROM & work at low saddle height (triathletes) • ↑Mean knee angles & ↓ mean hip angles at low & preferred compared to high & optimal saddle heights (all cyclists) • For triathletes, ↓ mean hip angle and ↑ hip ROM at preferred height compared to road cyclists.	• Road cyclists ↓effectiveness with saddle at optimal compared to preferred height; triathletes ↓ ankle work & ROM with saddle at optimal compared to low. • Optimal saddle position was up to 5% (road) -7% (triathlete) different from current saddle height.
Bini and Hume 2014	12	• 24 cyclists • 16 with knee pain) • Recreational • 40 ± 11 yrs (pain group), 43 ± 9 yrs (no pain group)	• Kinematics: sagittal hip, knee, ankle • Kinetics (2D): pedal forces, net joint moments (hip, knee, ankle), patellofemoral compressive & tibiofemoral compressive/ shear forces	• Conditions: Four 2min trials, submax effort, 4 saddle heights: 1) preferred, 2) low (-10 ° change in knee flexion angle at bottom dead center), 3) high (+10 ° change) 4) “optimal saddle height” (25 ° knee flexion). • Cycle: Stationary ergometer	• ↑ Anterior tibiofemoral peak forces at high and optimal compared to low saddle height • No differences in peak with and without knee pain across saddle conditions. • Large differences in knee angle with changing saddle heights.	• No differences seen in forces or kinematics with and without knee pain across saddle conditions. • Small sample size led to large within group variability.
Dieter et al., 2014	10	• 17 cyclists • 10 without pain (4 male), 7 with PFPS (6 male) • 46 ± 11.4 yrs, (pain group), 40 ± 12 yrs (no pain group)	• Kinematics: knee flexion • EMG: quadriceps, hamstrings	• Conditions: 30s at the end of each of 10 mins, 90 rpm, RPE score 14. • Cycle: Own cycles on trainer	• No significant difference seen in onset of quadriceps muscles between groups. Vastus medialis turned off sooner with pain. • Significant difference in onset of hamstrings (biceps femoris contracted sooner than semitendinosus in pain group). • Cyclists with pain had ↓ activation of semitendinosus.	• Onset of quadriceps activity not correlated to pain. Differences in offset of quadriceps may not contribute to altered joint mechanics but may contribute to pain. • It is not known if the differences seen are causal or compensatory.
Elmer et al., 2011	12	• 11 male cyclists • No injury • Experienced • 19-44 yrs	• Kinetics: 2D joint powers at hip, knee, ankle	• Conditions: 5 power outputs (250-850W), 90 rpm, 3sec submax efforts plus 2 max effort at 90 and 110 rpm • Cycle: Isokinetic ergometer	• ↑ Absolute power at hip, knee, ankle as cycling power↑. • As power output ↑, relative knee flexion power ↑ & extension ↓. • Hip extension power dominant in producing power, but relative hip extension power unchanged with ↑ power output	• Joint powers ↑ with higher power output. • As intensity ↓, knee flexion power is more important. • Hip extension power is important; cyclists may benefit from hip extensor strengthening.
Fang et al., 2016	12	• 18 cyclists • No injury • Recreational • 55.8 ± 11.0 yrs	• Kinematics: knee sagittal/coronal plane • Kinetics: knee sagittal/frontal plane moments	• Conditions. 2 mins, 8 conditions: 60 rpm, 5 workloads (0.5-2.5kg); 70, 80, 90 rpm at 1kg. • Cycle: Stationary ergometer	• ↑ workload led to ↑knee extension & abduction moments and ↑ knee vertical & medial pedal reaction forces. • ↑ cadence led to ↑ anterior & vertical pedal reaction forces and ↑ knee flexion moment.	• Differing effects of cadence and workload on knee forces.
Farrell et al., 2003	8	• 10 cyclists (6 male) • No injury • Recreational • 30.6 ± 5.5 yrs	• Kinematics: knee flexion, crank angle • Kinetics: pedal forces	• Conditions: 80-90 rpm, 280W, five 4s trials of 5 min ride, saddle height to obtain 25-30 ° knee flexion at bottom dead center. • Cycle: Standard cycle on trainer	• Minimum cycling knee flexion was 30-35 ° due to ↑ lateral pelvic motion. • Peak pedal forces of 290.9 ± 84.2 N at 110 ° of revolution. • Combined force & knee angle data showed that these cyclists not at risk for ITBS.	• Cyclists tested in these conditions are not at risk for ITB impingement. • Number of repetitions, anatomical differences, bike fit, & training may play more important roles in developing ITBS.
Ferrer-Roca et al., 2016	12	• 12 road cyclists • No injury • Amateur • 20.8 ± 2.8 yrs	• Kinematics: 2D hip, knee, ankle • Kinetics: crank torque	• Conditions: 3 submax efforts; 150, 200, 250 W; 3 crank lengths (preferred ± 5mm). • Cycle: Stationary ergometer	• ↑crank length led to ↑torque and ↑hip and knee ROM.	• ↓ crank length may ↓ torque at knee.
Gardner et al., 2015	13	• 24 non-cyclists • 13 with knee OA, 11 without OA • 56.8 ± 5.2 yrs (OA), 50.0 ± 9.7 yrs (non-OA)	• Kinematics (3D): knee and ankle sagittal/coronal • Kinetics: Pedal reaction forces, 3D hip, knee, ankle sagittal/coronal moments • Pain: Visual analog scale	• Conditions: Last 30s of a 2 min effort; 60 rpm; 80W; foot in neutral rotation plus 2 toe-in positions • Cycle: Stationary ergometer	• 5 ° and 10 ° wedges↑ knee adduction angles • No ↓ seen in knee abduction moments or knee pain. • ↑ vertical pedal reaction forces.	• Results mixed as knee adduction angles ↓ without change in abduction moment or pain, while vertical loading ↑. • ↓ knee adduction angles may reduce overuse injuries
Gregersen et al, 2006	3	• 15 cyclists • No injury • Competitive • 18-30 yrs	• Kinetics: Knee sagittal/ coronal moments • EMG: quadriceps, tensor fascia latae	• Conditions: 5 min effort, 90 rpm, 225W, 5 positions of ankle eversion/inversion • Cycle: Stationary ergometer	• ↑ Peak varus & average varus/valgus moments with inversion and ↓ with eversion. • Activation ratio of the vastus medialis to vastus lateralis ↑ with inversion	• Ankle eversion may prevent or ↓ patellofemoral pain.
Tamborin-deguy et al, 2011	10	• 9 male non-cyclists • No injury • 22-36 yrs	• Kinematics: knee sagittal plane • Kinetics (2D): pedal forces, tibiofemoral compressive/shear forces, & patellofemoral compressive force.	• Conditions: 1 minute, 70 rpm, 70W, 3 saddle heights (100, 103, 97% trochanteric height). • Cycle: Stationary ergometer	• No difference in peak tibiofemoral compressive/anterior shear components across heights. • ↑ knee flexion angle at lowest saddle height compared to other heights.	• Small changes in saddle height at low effort likely had little or no impact on joint loading. • Kinematic changes unrelated to forces in these conditions.

DB score = Downs and Black score; EMG = electromyography; ITB = iliotibial band; ITBS: iliotibial band syndrome; OA = osteoarthritis; PFPS = patellofemoral pain syndrome; ROM = range of motion; RPE; Rating of Perceived Exertion