Knees over Toes: Promoting Functional Range of Motion

Editorial

Movement patterns and optimal techniques have been controversial topics in the human performance field for many years of those, knee trajectory during squat patterns has been one of the most scrutinized. In general, there is a consensus among organizations and professionals regarding a more neutral trajectory from a lateral standpoint, thus mitigating knee valgus and varus. Despite research supporting the benefits of anterior knee displacement exceeding the toes [1], some organizations and professionals still discourage such patterns which continue to be expressed in research [2].

In recent years, this “Knees Over Toes” concept has been more widely accepted thanks to the marketing techniques of industry professionals like Ben Patrick, CEO of The Athletic Group [3]. In short, industry professionals like Patrick have promoted the application of full ankle and knee range of motion while promoting anterior displacement of the knee exceeding the toes during various squatting and lunging patterns. For example, Patrick incorporates exercises like the KOT Calf Raise, the Patrick Step, and the ATG Split Squat which all encourage anterior knee movement surpassing the toes [4]. Interestingly, many rehabilitation professionals have been using similar techniques for years but, by anecdote, had not marketed the concept successfully to the general population.

Squatting with the knees past the toes anteriorly has shown increases in quadriceps force and patellofemoral joint stress [5]. Research has also noted an increase in rectus femoris and gastrocnemius activation with increasing decline angles in decline/slant board squats, commonly used to promote or supplement anterior knee translation during squatting patterns [6]. Unilateral applications have also exhibited benefit by mitigating medial knee translation (knee valgus) and lateral hip translation during single-leg squats, promoting a more optimal alignment [7].

Ultimately, evidence validates the application of anterior knee translation during squatting patterns in some instances. Some researchers have distinguished the biomechanical differences between common squat formats which may have associated preferences depending on intended outcomes. For example, the traditional barbell squat typically exhibits greater anterior knee displacement than a powerlifting squat which tends to be more hip-dominant [8].  Otherwise, effective decline squat programs (eccentric or heavy, slow load) can effectively facilitate modest cases of patellofemoral pain when individuals aren’t concurrently exposed to high-volume sport demands [9].

Anterior knee translation during squatting patterns requires notable ankle dorsiflexion ability [8]. Restricted ankle dorsiflexion is associated with a greater incidence of knee valgus and patellofemoral knee pain [10], reduced knee flexion [11], and increased forward trunk lean [12] during squat and/or lunge patterns. Moreover, reduced ankle dorsiflexion has also exhibited strong correlations with reduced countermovement jump performance [13]. Considering the “Knees Over Toes” approach is aimed to enhance ankle dorsiflexion ability and knee extensor functionality, it’s unsurprising that this methodology has yielded mostly favorable results [3].

For practitioners, the use of squat and lunge patterns with anterior knee displacement exceeding the toes should generally be considered appropriate if reasonable and progressive methods are used. Additionally, further examination should investigate the medial/lateral trajectory of the knee to ensure appropriate tracking, typically over the second toe [14]. These applications may be limited by insufficient ankle dorsiflexion. Thus, squats and lunges with anterior knee displacement exceeding the toes have shown merit in both athletic and rehabilitative settings. Decline/slant boards are typically appropriate to promote greater knee flexion angles and functionality in those with restricted ankle dorsiflexion [6].

Further research should investigate the reliability of these methods in preventative contexts to mitigate patellofemoral and anterior cruciate ligament (ACL) injuries. Additionally, no clear evidence indicates the degree to which the knee should flex or translate anteriorly past the toes without repercussions to menisci or articular cartilage despite potential improvements in musculotendinous functionality [15]. It’s possible that other biomechanical factors related to knee valgus and trunk angle are greater contributors to articular knee injuries, in part related to reduced ankle dorsiflexion [7, 10, 12, 16], but this remains to be thoroughly investigated.

References

1. Fry AC, Smith JC, Schilling BK (2003) Effect of knee position on hip and knee torques during the barbell squat.  J Strength Cond Res17(4): 629-633.
2. Vithanage SS, Ratnadiwakara MS, Sandaruwan D, Arunathileka S, Weerasinghe M et al. (2020). Identifying Muscle Strength Imbalances in Athletes using Motion Analysis Incorporated with Sensory Inputs. International Journal of Advanced Computer Science and Applications, 11(4): 811-818.
3. Dolinger J (2022) Review of Effective Injury Preventing and Performance Enhancing Strategies for Runners. Submitted to the Department of Sport, Exercise, Recreation, and Kinesiology, East Tennessee State University, USA.
4. Patrick B (2021). Knee ability zero. Ben Patrick.
5. Kernozek TW, Gheidi N, Zellmer M, Hove J, Heinert BL, et al. (2018) Effects of anterior knee displacement during squatting on patellofemoral joint stress. J Sport Rehabil27(3): 237-243.
6. Lomba, N, Vilas-Boas JP, Roriz, P (2021) Decline angle effects on the lower limb biomechanics of the squat rehabilitation exercise: A systematic review. Advances and Current Trends in Biomechanics, 216-220.
7. Freke MD, Crossley K, Russell T, Sims KJ, Semciw A (2019) Changes in Knee and Trunk Alignment in People With Hip Pain and Healthy Controls When Using a Decline Board During Single-Leg Squat. J Sport Rehabil 29(7): 886-896.
8. Swinton PA, Lloyd R, Keogh JW, Agouris I, Stewart AD. (2012) A biomechanical comparison of the traditional squat, powerlifting squat, and box squat.  J Strength Cond Res 26(7): 1805-1816.
9. Malliaras P, Cook J, Purdam C, Rio E (2015) Patellar tendinopathy: clinical diagnosis, load management, and advice for challenging case presentations.  J Orthop Sports Phys Ther 45(11): 887-898.
10. Coelho BAL, das Neves Rodrigues HL, Almeida GPL, João SMA (2021) Immediate effect of ankle mobilization on range of motion, dynamic knee valgus, and knee pain in women with patellofemoral pain and ankle dorsiflexion restriction: a randomized controlled trial with 48-hour follow-up. J Sport Rehabil 30(5): 697-706.
11. Dill KE, Begalle RL, Frank BS, Zinder SM, Padua DA (2014) Altered knee and ankle kinematics during squatting in those with limited weight-bearing–lunge ankle-dorsiflexion range of motion.  J Athl Train 49(6): 723-732.
12. Fuglsang EI, Telling AS, Sørensen H (2017) Effect of ankle mobility and segment ratios on trunk lean in the barbell back squat.  J Strength Cond Res31(11): 3024-3033.
13. Godinho I, Pinheiro BN, Júnior LDS, Lucas GC, Cavalcante JF, et al. (2019) Effect of reduced ankle mobility on jumping performance in young athletes. Motricidade, 15(2-3): 46-51.
14. Lim E H, Kim ME, Kim SH, Park KN (2020) Effects of posterior X taping on movement quality and knee pain intensity during forward-step-down in patients with patellofemoral pain syndrome.  J Sports Sci Med19(1): 224.
15. Schoenfeld BJ (2010) Squatting kinematics and kinetics and their application to exercise performance.  J Strength Cond Res24(12): 3497-3506.
16. Kianifar R, Lee A, Raina S, Kuli? D (2017). Automated assessment of dynamic knee valgus and risk of knee injury during the single leg squat.  IEEE J Transl Eng Health Med 5: 1-13.