When Positive Keyboard Tilt Actually Makes Sense: The Biomechanics Most Ergonomists Miss

Discover why positive keyboard tilt is sometimes the right ergonomic choice. Learn the biomechanical principle that determines keyboard angle and when to break the standard rules. Research-backed guidance for ergonomics professionals.

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Transcript

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Well, hey there. Welcome to the Business of Ergonomics podcast. Today in the show, we are gonna be talking about positive keyboard tilt. Yeah, you heard it. We're gonna be talking about situations where the positive keyboard tilt makes sense. We're gonna be looking at the biomechanics of non-standard workstation configurations, so grab on to your hats, grab that cup of coffee and let's do this. Welcome to the Business of Ergonomics podcast. I'm your host, Darcy Jeremy. I'm a board certified professional agonist with over 15 years of experience delivering ergonomics programs to employers of all different types. In this podcast, I share what other healthcare professionals are already doing and being with ergonomics assessments and how to land those clients that you dream of. Without further ado, let's jump into this episode right now. So pumped that we're gonna be diving into something that may seem a little bit counterintuitive to you at first, because after all, this is an ergonomics podcast and we're all about neutral posture. But trust me, at the end of today's episode, you're gonna have a fully new perspective on keyboard positioning. Yep. We're talking about keyboard tilt. You may remember in the past episode I was talking about something that. Was kind of near and dear to my heart where I was consulting to a particular client and I needed to have a unique solution for them, which involved a positive keyboard tilt. And I wanted to dive a little bit more into what that means for us as ergonomics professionals, because really when we're talking about positive keyboard tilt. That's generally what we have been trained to avoid doing. We're talking about those keyboard feet that we tell our clients to fold down, you know, at the back of their keyboard. But there are actually some legitimate scenarios where a positive tilt is exactly what the workstation needs. This episode is designed for my fellow ergonomics professionals. But it's also gonna be incredibly valuable for those of you who are just starting your ergonomics journey into assessments. Because here's the thing, ergonomics isn't about rigid rules. It's about understanding the core biomechanical principles and then applying them them to each situation that you see as an ergonomics consultant. And if you can do that consistently, then boom, you are making it. I am gonna be sharing a personal story from early in my career too, to kind of take the layers off from the onion on what this really means on how to address the situation and assessments. It was one of those moments when the textbook answer felt wrong and when I first applied. These types of processes and everything kind of clicked into place. So we gotta start here. When we're looking at applying these principles, one thing really comes into play and it's that neutral position. Why does it matter so much in our work? And obviously we know that because neutral position is everything for us when we are ergonomics professionals. And before we can learn to break the rules, we need to understand why these neutral posture rules exist in the first place. it all comes down to what the documents are saying about this. So if we just wanna look at what OSHA says about computer workstations, it defines a neutral posture as a comfortable working posture in which. Your joints are naturally aligned, and that's really key. The positioning reduces stress and strain on the muscles, the tendons and the skeletal system, and reduces your risk of developing an MSD. Let's look a little bit more at the wrist specifically. And really neutral posture means a straight line from the forearm through to the hand with minimal deviation in any plane. When we talk about wrist deviation, we're looking at three primary movements that can deviate from neutral. First, we're looking at flexion and extension in the sagittal plane, and that's basically, you know, bending the wrist up or down. Second, we're looking at radial and ulnar deviation in the frontal plane, and that's side to side wrist movements. Third, we're looking at forearm, pronation, and supination, which we all know is the rotation of the forearm. here's what research tells us. A fascinating 2004 study published in clinical biomechanics. Measured what they called the angular wrist neutral zone. They had blindfolded participants position their wrists where they felt most natural, the results, while participants consistently positioned their wrists at seven to nine degrees of extension and five to seven degrees of ulnar deviation. This is important because it tells us that neutral posture isn't perfectly flat. There's a small natural range, but here's where it gets interesting. when participants deviated beyond the zone, EMG activity in the forearm muscles increased significantly. This study showed that self-selected neutral posture, decreased muscle activity compared to forced deviations. Now, why does this matter? Because prolonged deviation from neutral increases internal tissue pressure research by Rempel and his colleagues published in the Journal of Orthopedic Research in 2008 demonstrated that risk extension and radial deviation independently increased carpal tunnel. They found that the activity of typing itself elevated carpal tunnel pressure above static hand positions and non neutral postures compounded that effect the ANSI 2007 standard codifies this understanding. It recognizes four primary reference postures. Upright seated, reclined seated decline, seated and standing. Notice that the standard doesn't advocate for just one posture. It acknowledges that different postures can all be neutral if the joints remain in their neutral and natural alignment. This is a critical distinction that some practitioners miss. The goal here isn't to force everyone into the same position. The goal is to support neutral joint alignment regardless of the overall body posture. Alright, let's dive into why in standard workstation configurations we recommend neutral. Or negative keyboard tilt. This is the foundation that we need to understand before we can intelligently deviate from it. When a person sits in a typical upright seated posture at a standard desk, the forearms naturally angle slightly downward from the elbow to the hands. If you place a keyboard flat on a desk or worse, prop it up with the keyboard feet. You create a mismatch. The keyboard surface angle is upward while the forearms angle downward. What happens? Biomechanically? Well, the wrist must compensate by extending bending upward to reach the keys. This is extension in the wrist Research from Cornell University's ergonomics program describes this phenomenon. In this position, it is difficult to maintain the wrist in a neutral posture because the forearms sag as they tire, and this puts the wrist into greater wrist extension. The Landmark 1995 study by Hedge and powers published in ergonomics used video motion analysis to examine the hand and wrist postures during typing, they found that dorsal wrist extension average 13 degrees when typing at a standard desk without support. However, when they introduced a negative slope keyboard support system angled 12 degrees below, horizontal wrist extension dropped to essentially zero degrees. That's a 13 degree improvement in wrist posture. The physiological implications are significant. In 2003, Semino, marclin and Berman published research in physical therapy showing that keyboard slope affects not just posture, but muscle activity. They tested keyboard slopes from positive. 7.5 degrees to negative 15 degrees Wrist extension decreased from approximately 12 degrees with a positive slope to three degrees of flexion with a negative 15 degree slope. Importantly, the EMG activity of the extensor carpi ners muscle decreased by 63% when using the negatively sloped keyboard. 63% reduction in wrist extensor muscle activity. That's the difference between sustainable typing and cumulative strain. Woods and Babs Ski Reeves in their 2005 study published in ergonomics examined negative keyboard angles from zero to negative 30 degrees. They found that negative angles in general provide significant reductions in exposure to deviated wrist postures and muscle activity. Rempel and colleagues demonstrated that carpal tunnel pressure increases proportionally with risk deviation. Weiss Gordon Bloom Sow and Rempel in their 1995 study in the Journal of Bone and Joint Surgery identified that the position of the wrist associated with the lowest carpal tunnel pressure is slight flexion. Not extension. a 2023 study investigating keyboard inclinations for sitting and standing Workstations confirmed this, although users prefer to use positive keyboard angle, the negatively tilted keyboard is more ergonomically friendly at both sitting and standing workstation. So the science is clear in standard configurations negative. Or neutral Tilt keeps the wrist aligned with the natural downward angle of the forearms. this minimizes extension and reduces both muscle activity and carpal tunnel pressure. But here's the key insight. All of this research assumes a standard upright seated posture. What happens when the posture isn't standard? Now we actually get to the heart of today's episode. When does positive keyboard tilt actually support neutral posture? The answer here lies in understanding that keyboard tilt isn't relative to form angle all the time and forearm angles change with body posture. Obviously, the an C 2007 standard specifically recognizes. The reclined sitting posture is one of the four acceptable reference postures in reclined sitting. The user's torso and neck are straight and reclined between 105 and 120 degrees from the thighs. Here's what happens. Biomechanically in a reclined posture, as the torso reclines backward, the shoulder position changes. The arms if relaxed at the sides, now naturally point more forward and slightly upward relative to the horizontal plane. If the keyboard remains flat on the desk or negatively tilted, the user must now flex their wrist downward to reach the keys, and that's the opposite problem of the standard scenario. Research from Herman Miller's studies on the kinematics of sitting supports this. They reference studies by Ian and colleagues from 1983 showing that a slightly reclined sitting posture is often preferred for keyboarding and mouse. The key is the workstation must adapt to this posture. A 2008 study published in the International Journal of Industrial Ergonomics by Hanes and colleagues examined typing from significantly reclined and supine postures. They found that traditional upright workstation configurations are not appropriate for reclined work because the input devices need to be repositioned to match the changed body geometry. Think about it this way, the principle is always the same. Align the keyboard surface with the natural forearm angle to maintain a neutral wrist in upright sitting forearms angle slightly downward. So we tilt the keyboard down. In recline sitting, the forearms may angle slightly upward relative to the horizontal, so we tilt the keyboard up to match. The CSA standard Z 4 12 17 on office ergonomic states that. Variations of sitting and standing postures, including reclining forward, tilting and semi standing are encouraged. In order to avoid the negative effects of prolonged sitting or standing in one posture, this explicitly acknowledges that workstations must accommodate these variations. The Spine Research Institute at Ohio State University has researched spinal loading and reclined postures. Their findings indicate that reclined postures can reduce spinal loads by transferring some body weight to the seat back. However, they know that the workstation must be appropriately configured to support interaction with computer equipment in these positions Okay, y'all, for ergonomics consultants out there in the field, here's the framework. If the forearm angle relative to horizontal is positive, pointing upward, then the keyboard should also match and have a positive tilt. To maintain neutrality, the magnitude of the tilt should match the forearm angle. So I wanna share a story from early in my career that fundamentally shaped how I approach workstation assessments. When I was first starting out in office ergonomics assessments, I was called to evaluate the workstation of a middle aged man who had to be an experiencing some discomfort. He was working in a deeply reclined position. His chair was leaned way back. I'm talking way back well beyond what I had been taught was appropriate. My first instinct was to tell him to sit up straight, to adjust his chair to a more upright position. But something made me pause. I asked him about his preference. And he was super clear here. He liked working this way. He's done it forever. It was comfortable for him and he enjoyed it. So instead of fighting against his preference, I decided to apply what I now think as a first principles of ergonomics here. I asked myself, what's the actual goal here? The goal is neutral joint alignment. How do I achieve neutral joint alignment for someone in a reclined posture? I started by observing his natural forearm position. When he relaxed his arms at the sides while reclined, his forearms angled upwards. They weren't parallel to the ground. They were pointing toward the ceiling at a slight angle. this meant that a standard keyboard position flat or negatively tilted, would force him to flex his wrists downward. That still deviation from neutral. The direction is different, but the strain is similar. So I did something that I felt was a bit counterintuitive at the time. I adjusted his workstation tray to a positive tilt. I matched the angle of the keyboard surface to the natural angle of his forearms, and when I stepped back to observe, his wrists were straight. They were absolutely neutral. The keyboard surface was now parallel to his forearm axis, but here's where it got even more interesting. His monitor position was now wrong in a reclined posture, the natural line of sight changes. So in combination of. The positive keyboard tray. I also tilted the monitor downward and lowered it to align with his new line of sight. Again, counterintuitive if you're thinking the monitors at eye level, but the principle is the same. Align the equipment with the body, not the other way around. When I stepped back to assess the whole setup. Every segment was within what we consider aligned and neutral. The wrist restraint relative to the forearms. The forearms aligned with the keyboard surface. The neck was neutral relative to the torso. The eyes looked naturally at the tilted monitor without having to crane the neck back. It looked completely different from a textbook workstation. But every joint was neutral in a supported position. The geometry was consistent with biomechanical principles just applied to, to a non-standard overall posture. This was a turning point for me. I realized that ergonomics is not about enforcing a single correct setup. It's about understanding the principles deeply enough that you can apply them to any situation that you see. Beyond deeply reclined seating. there are several other scenarios where positive keyboard tilt might be appropriate. The first one being zero gravity workstations, they're becoming popular. They're kind of cliche, but these can be useful for workers with chronic low back pain. The research by Hayes and colleagues specifically examined supine and significantly reclaimed postures for people with lower back pain who need to minimize spinal loads while still maintaining productivity. In these configurations, the keyboard often needs to be oriented with a positive tilt, quite steep. To match the upward facing forearm position. Another example is executive chair users. Many executive level workers prefer the appearance and comforts of high back chairs with significant reclined capability. Rather than fighting this preference, the effective person is gonna be able to adapt a workstation to support neutral posture within the reclined position. Another example is control room operators in industrial control rooms, security monitoring stations, and similar environments. Workers often spend extended shifts in reclined seating designed for sustained attention tasks. The keyboard position must accommodate this too, so we're otherwise there. Some workers with mobility impairments, spinal conditions, or chronic pain may require reclined position. The keyboard tilt becomes part of the accommodation strategy, and in some situations, a recent one that I saw, sometimes a standing workstation isn't enough. When that client is sitting, they may need to have a super reclined sitting position with a keyboard tray installed, even though they have a standing workstation. That's really something to accommodate because it can increase the productivity of the worker substantially. Imagine there's someone laying flat on their back using a computer like in a hospital bed, or like a zero gravity workstation. Their forearms would naturally point almost straight up. A keyboard in that scenario would need to be nearly vertical to achieve neutral risk posture. While extreme, this illustrates the principle perfectly, the keyboard orientation follows the forearm orientation. Alright, you know me, I love when I can make this podcast as practical as possible for you, and if you. Encounter a worker who prefers or requires a reclined posture. I wanted to put together some steps on how to approach the assessment. So I have outlined a seven step process of what you can do to really hit a home run here. Step one would be to establish the baseline posture, have the worker recline to their comfortable or required position. Note the angle of the backrest from vertical. And that basically becomes reference. Step two is to observe the natural forearm angle. Ask the worker to relax their arms at their sides while reclined. Where do their forearms naturally point? Are they horizontal, angled upwards, or somewhere in between? Step three, match the keyboard surface. Adjust the keyboard tray, or support to match the forearm angle. the surface of the keyboard should be parallel to the forearm when the arm is in a relaxed typing position. Step four, check the wrist posture. This is like the big thing that you gotta do here with the keyboard in the matched angle. Have the worker place their hands on the keys. The rest should remain in a neutral position straight. Not flexed or extended adjust as needed. Step five, adjust the workstation height. The keyboard should be at an approximately elbow height with a reclined posture. This may require lowering the keyboard position relative to a standard desk. Step six, adjust the monitor. The natural line of sight is not. downward, it's actually upward, so the monitor should be tilted upward to maintain the natural viewing angle. Step seven. Document your rationale when you make non-standard recommendations. Document the biomechanical reasoning. Note the overall posture resulting from the forearm angle and how the keyboard tilt maintains neutral wrist posture. Step eight. You wanna ensure that everything else in that worker's. Workstation is set up for neutral posture and provide education when they are varying their postures throughout the workday. What do they need to know about the chair setup? What do they need to know about other workstation adjustments? Do they know how to make the adjustments to the keyboard tray, the keyboard tray angle, the backrest angle? Various mechanisms of the chair as well. These are something to ensure that client knows in and out before you leave, because there is a lot more responsibility here because that chair is in such a reclined position Let's take a step back here. Take like a 30,000 foot view why we should be even caring about something like this in our profession. First, it's about credibility, right? When we rigidly apply rules without understanding the principles behind them, we lose our credibility with workers who know their own comfort levels. The worker who prefers reclined seating isn't wrong, and they may actually be reducing their spinal load as the research shows. We're not the ergonomic police here. We're there to observe and optimize posture, not force them into a position they'll abandon as soon as we leave We're here to support the worker and optimize their workstation set up. Second, it's about effectiveness. The goal of ergonomics is to reduce injury, risk, improve comfort, and improve or enhance productivity, all that together, right? If our recommendations aren't followed because they conflict with personal preferences or actual need, they achieve nothing. Understanding when to adapt our recommendations makes us way more effective. Practitioners creates no like, and trust can bring in referrals. You name it, but this should be a foundation of everything we offer when it comes to ergonomics. Third, it's really about the evolution of our field too. We all know that work is changing and especially with improvements in technology that allows chairs to be more reclined in the first place, whether it's remote work, alternatives, workstations, zero gravity, chairs, and accessibility, the needs are creating situations that traditional frameworks and guidelines didn't anticipate. The peer reviewed research cited today from pel, from hedge, from Semino, from ansi, all points to the same underlying principle, maintain neutral joint alignment. How you achieve that alignment depends on the specific situation. Of course. If today's episode resonated with you, and if you appreciate this approach of understanding principles deeply so that you can apply them intelligently, then I wanna tell you about two programs that can accelerate your ergonomics journey. the ergonomics blueprint. Is our comprehensive training program designed to give you the foundational knowledge and practical skills you need to conduct professional ergonomics assessments. This isn't about memorizing checklists. It's about developing the principle based understanding we discussed today. We cover biomechanics, assessment methodology, intervention strategies, and the business side of ergonomics consulting. Whether you're new to the field or looking to formalize your expertise, the blueprint provides the structured pathways you. I also offer a program called Accelerate the Business of Ergonomics. This is our ongoing membership program for practitioners who want to build and grow their ergonomics practice beyond the technical skills. You need to know about how to market your services, price your assessments, deliver value that keeps clients coming back and scale your business sustainably. Accelerate provides monthly coaching, a community of peers, resources, templates, and ongoing support. You need to build a thriving ergonomics practice. If you're serious about ergonomics, whether as a career path or as an addition to your practice. These programs give you the edge. Visit the show notes to get the details of how you can get started today. So let's recap what we talked about. An anatomical neutral position is the foundation of ergonomics, obviously. For the wrist neutral means a straight line from forearm through the hand deviation from neutral increases carpal tunnel pressure and muscle activity, and standard upright sitting forearms angle slightly downward, so negative keyboard tilt, aligns the keyboard with the forearms and maintains wrist neutrality. The research consistently supports this. However, in reclined sitting postures, forearms may angle upward. In these cases, a positive keyboard tilt may be necessary to maintain the same wrist neutrality. The principle doesn't change, only the application does. When configuring reclined workstations, remember to adjust the monitor position too. Tilt it down to align with the changed line of sight. You always wanna document your non-standard recommendations with biomechanical rationale. This protects you professionally and educates others. As practitioners, our value is not enforcing rules. It's an understanding. Principle is deeply enough to apply them in any situation we encounter. Thanks for joining me on the Business of Ergonomics podcast. If you found this episode valuable, share it with a colleague. Subscribe to it so you can be the latest to know when podcasts are released, And don't forget to grab the lead magnet I've created for this episode, a decision guide for non-standard keyboard position that you can reference in the field. All you have to do is go to the show notes to find where to grab this download. Until next time, my friends keep on applying the principles, not just the rules. No one wants their ergonomics to be policed. You can get started with office ergonomics assessments. Today, healthcare professionals are seeing the potential and opportunity to add office ergonomics assessments to their practice and services. Go to ergonomics help.com. Slash begin to get the exact seven step process that works so that you can get started today without the confusion or overwhelm. Just head to ergonomics help.com/begin now.